Pull web components from androidx-compose

.gitignore

@@ -1,30 +1,3 @@
-# Intellij files
-
-.idea/*
-!.idea/copyright
-!.idea/scopes
-
-# Mac OS files
-
-.DS_Store
-
-# Compiled class file
-*.class
-
-# Log file
-*.log
-
-# Package Files #
-*.jar
-!gradle-wrapper.jar
-
-*.war
-*.nar
-*.ear
-*.zip
-*.tar.gz
-*.rar
-
-# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
-hs_err_pid*
-
+//gradle
+build
+.gradle

web/build.gradle

@@ -0,0 +1,4 @@
+plugins {
+    id("org.jetbrains.kotlin.multiplatform") version("1.4.32") apply(false)
+    id("org.jetbrains.compose") version "0.0.0-web-dev-12" apply(false)
+}

web/core/build.gradle

@@ -0,0 +1,49 @@
+plugins {
+    id("kotlin-multiplatform")
+    id("org.jetbrains.compose")
+}
+
+
+kotlin {
+    jvm()
+    js(IR) {
+        browser() {
+            testTask {
+                testLogging.showStandardStreams = true
+                useKarma {
+                    useChromeHeadless()
+                    useFirefox()
+                }
+            }
+        }
+        binaries.executable()
+    }
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation(compose.runtime)
+                implementation(kotlin("stdlib-common"))
+            }
+        }
+
+        jsMain {
+            dependencies {
+                implementation(kotlin("stdlib-js"))
+                implementation(npm('css-typed-om', '0.4.0'))
+            }
+        }
+
+        jsTest {
+            dependencies {
+                implementation kotlin("test-js")
+            }
+        }
+
+        jvmMain {
+            dependencies {
+                implementation(compose.desktop.currentOs)
+            }
+        }
+    }
+}

web/core/src/commonMain/kotlin/withWeb/Alignment.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui
+
+interface Alignment {
+    interface Vertical : Alignment
+    interface Horizontal : Alignment
+
+    companion object {
+        val TopStart = object : Alignment {}
+        val TopCenter = object : Alignment {}
+        val TopEnd = object : Alignment {}
+        val CenterStart = object : Alignment {}
+        val Center = object : Alignment {}
+        val CenterEnd = object : Alignment {}
+        val BoottomStart = object : Alignment {}
+        val BoottomCenter = object : Alignment {}
+        val BoottomEnd = object : Alignment {}
+
+        val Top = object : Alignment.Vertical {}
+        val CenterVertically = object : Alignment.Vertical {}
+        val Bottom = object : Alignment.Vertical {}
+
+        val Start = object : Alignment.Horizontal {}
+        val CenterHorizontally = object : Alignment.Horizontal {}
+        val End = object : Alignment.Horizontal {}
+    }
+}

web/core/src/commonMain/kotlin/withWeb/Arrangement.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+object Arrangement {
+    interface Horizontal
+    interface Vertical
+
+    val End = object : Horizontal {}
+    val Start = object : Horizontal {}
+    val Top = object : Vertical {}
+    val Bottom = object : Vertical {}
+}

web/core/src/commonMain/kotlin/withWeb/Color.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.core.graphics
+
+public data class Color(val red: Int, val green: Int, val blue: Int) {
+
+    companion object {
+        val Black = Color(0, 0, 0)
+        val DarkGray = Color(0x44, 0x44, 0x44)
+        val Gray = Color(0x88, 0x88, 0x88)
+        val LightGray = Color(0xCC, 0xCC, 0xCC)
+        val White = Color(0xFF, 0xFF, 0xFF)
+        val Red = Color(0xFF, 0, 0)
+        val Green = Color(0, 0xFF, 0)
+        val Blue = Color(0, 0, 0xFF)
+        val Yellow = Color(0xFF, 0xFF, 0x00)
+        val Cyan = Color(0, 0xFF, 0xFF)
+        val Magenta = Color(0xFF, 0, 0xFF)
+    }
+}

web/core/src/commonMain/kotlin/withWeb/Modifier.kt

@@ -0,0 +1,12 @@
+package org.jetbrains.compose.common.ui
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.core.graphics.Color
+
+interface Modifier {
+    open class Element : Modifier
+    companion object : Element()
+}
+
+expect fun Modifier.background(color: Color): Modifier
+expect fun Modifier.padding(all: Dp): Modifier

web/core/src/commonMain/kotlin/withWeb/layouts/box.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+
+@Composable
+internal expect fun BoxActual(modifier: Modifier, content: @Composable () -> Unit)

web/core/src/commonMain/kotlin/withWeb/layouts/button.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+
+@Composable
+expect fun ButtonActual(
+    modifier: Modifier,
+    onClick: () -> Unit,
+    content: @Composable () -> Unit
+)

web/core/src/commonMain/kotlin/withWeb/layouts/column.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+
+@Composable
+internal expect fun ColumnActual(modifier: Modifier, content: @Composable () -> Unit)

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/BoxDefault.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+
+@Composable
+fun Box(
+    modifier: Modifier = Modifier.Companion,
+    content: @Composable () -> Unit
+) { BoxActual(modifier, content) }

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/ButtonDefault.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+
+@Composable
+fun Button(
+    modifier: Modifier = Modifier.Companion,
+    onClick: () -> Unit,
+    content: @Composable () -> Unit
+) {
+    ButtonActual(modifier, onClick, content)
+}

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/ColumnDefault.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+
+@Composable
+fun Column(
+    modifier: Modifier = Modifier.Companion,
+    content: @Composable () -> Unit
+) { ColumnActual(modifier, content) }

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/ModifierDefault.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui
+
+import org.jetbrains.compose.common.ui.unit.Dp
+
+fun Modifier.size(size: Dp): Modifier {
+    return size(size, size)
+}

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/RowDefault.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Alignment
+
+@Composable
+fun Row(
+    modifier: Modifier = Modifier.Companion,
+    horizontalArrangement: Arrangement.Horizontal = Arrangement.Start,
+    verticalAlignment: Alignment.Vertical = Alignment.Top,
+    content: @Composable () -> Unit
+) { RowActual(modifier, horizontalArrangement, verticalAlignment, content) }

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/SliderDefault.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Modifier
+
+@Composable
+fun Slider(
+    value: Float,
+    onValueChange: (Float) -> Unit = {},
+    valueRange: ClosedFloatingPointRange<Float> = 0f..1f,
+    steps: Int = 0,
+    modifier: Modifier = Modifier.Companion
+) {
+    SliderActual(
+        value,
+        onValueChange,
+        valueRange,
+        steps,
+        modifier
+    )
+}

web/core/src/commonMain/kotlin/withWeb/layouts/defaults/TextDefault.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.ui.unit.TextUnit
+
+@Composable
+fun Text(
+    text: String,
+    modifier: Modifier = Modifier.Companion,
+    color: Color = Color.Black,
+    size: TextUnit = TextUnit.Unspecified
+) {
+    TextActual(text, modifier, color, size)
+}

web/core/src/commonMain/kotlin/withWeb/layouts/row.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Alignment
+
+@Composable
+internal expect fun RowActual(
+    modifier: Modifier,
+    horizontalArrangement: Arrangement.Horizontal,
+    verticalAlignment: Alignment.Vertical,
+    content: @Composable () -> Unit
+)

web/core/src/commonMain/kotlin/withWeb/layouts/shapes/shapes.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package jetbrains.compose.common.shapes
+
+interface Shape
+
+object CircleShape : Shape

web/core/src/commonMain/kotlin/withWeb/layouts/slider.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Modifier
+
+@Composable
+expect fun SliderActual(
+    value: Float,
+    onValueChange: (Float) -> Unit,
+    valueRange: ClosedFloatingPointRange<Float>,
+    steps: Int,
+    modifier: Modifier,
+)

web/core/src/commonMain/kotlin/withWeb/layouts/text.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.ui.unit.TextUnit
+
+@Composable
+expect fun TextActual(
+    text: String,
+    modifier: Modifier,
+    color: Color,
+    size: TextUnit
+)

web/core/src/commonMain/kotlin/withWeb/modifiers/border.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.ui.Modifier
+
+expect fun Modifier.border(size: Dp, color: Color): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/clickable.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation
+
+import org.jetbrains.compose.common.ui.Modifier
+
+expect fun Modifier.clickable(onClick: () -> Unit): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/clip.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.draw
+
+import org.jetbrains.compose.common.ui.Modifier
+import jetbrains.compose.common.shapes.Shape
+
+expect fun Modifier.clip(shape: Shape): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/fillMaxHeight.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+
+expect fun Modifier.fillMaxHeight(fraction: Float): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/fillMaxWidth.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+
+expect fun Modifier.fillMaxWidth(): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/offset.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.ui.Modifier
+
+expect fun Modifier.offset(x: Dp, y: Dp): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/onSizeChanged.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.unit.IntSize
+
+expect fun Modifier.onSizeChanged(
+    onSizeChanged: (IntSize) -> Unit
+): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/size.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui
+
+import org.jetbrains.compose.common.ui.unit.Dp
+
+expect fun Modifier.size(width: Dp, height: Dp): Modifier

web/core/src/commonMain/kotlin/withWeb/modifiers/width.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.ui.Modifier
+
+expect fun Modifier.width(size: Dp): Modifier

web/core/src/commonMain/kotlin/withWeb/units/Dp.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.unit
+
+data class Dp(val value: Float)

web/core/src/commonMain/kotlin/withWeb/units/IntSize.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.unit
+
+data class IntSize(val width: Int, val height: Int)

web/core/src/commonMain/kotlin/withWeb/units/TextUnit.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.unit
+
+enum class TextUnitType {
+    Unspecified,
+    Em,
+    Sp
+}
+
+data class TextUnit(val value: Float, val unitType: TextUnitType) {
+    companion object {
+        val Unspecified = TextUnit(Float.NaN, TextUnitType.Unspecified)
+    }
+}

web/core/src/commonMain/kotlin/withWeb/units/unitConversion.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.ui.unit
+
+// TODO: this have to be in a separate package otherwise there's an error for in cross-module usage (for JVM target)
+val Int.dp: Dp
+    get() = Dp(this.toFloat())
+
+val Int.em: TextUnit
+    get() = TextUnit(toFloat(), TextUnitType.Em)
+
+val Float.em: TextUnit
+    get() = TextUnit(this, TextUnitType.Em)
+
+val Int.sp: TextUnit
+    get() = TextUnit(toFloat(), TextUnitType.Sp)
+
+val Float.sp: TextUnit
+    get() = TextUnit(this, TextUnitType.Sp)

web/core/src/jsMain/kotlin/androidx/compose/web/DomApplier.kt

@@ -0,0 +1,155 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web
+
+import androidx.compose.runtime.AbstractApplier
+import androidx.compose.web.attributes.WrappedEventListener
+import androidx.compose.web.css.StyleHolder
+import androidx.compose.web.css.attributeStyleMap
+import androidx.compose.web.elements.setProperty
+import androidx.compose.web.elements.setVariable
+import kotlinx.browser.document
+import kotlinx.dom.clear
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.Node
+import org.w3c.dom.get
+
+class DomApplier(
+    root: DomNodeWrapper
+) : AbstractApplier<DomNodeWrapper>(root) {
+
+    override fun insertTopDown(index: Int, instance: DomNodeWrapper) {
+        // ignored. Building tree bottom-up
+    }
+
+    override fun insertBottomUp(index: Int, instance: DomNodeWrapper) {
+        current.insert(index, instance)
+    }
+
+    override fun remove(index: Int, count: Int) {
+        current.remove(index, count)
+    }
+
+    override fun move(from: Int, to: Int, count: Int) {
+        current.move(from, to, count)
+    }
+
+    override fun onClear() {
+        // or current.node.clear()?; in all examples it calls 'clear' on the root
+        root.node.clear()
+    }
+}
+
+class DomNodeWrapper(val node: Node) {
+
+    constructor(tag: String) : this(document.createElement(tag))
+
+    private var currentListeners: List<WrappedEventListener<*>> = emptyList()
+    private var currentAttrs: Map<String, String?> = emptyMap()
+
+    fun updateProperties(list: List<Pair<(HTMLElement, Any) -> Unit, Any>>) {
+        val htmlElement = node as? HTMLElement ?: return
+        list.forEach { it.first(htmlElement, it.second) }
+    }
+
+    fun updateEventListeners(list: List<WrappedEventListener<*>>) {
+        val htmlElement = node as? HTMLElement ?: return
+
+        currentListeners.forEach {
+            htmlElement.removeEventListener(it.event, it)
+        }
+
+        currentListeners = list
+
+        currentListeners.forEach {
+            htmlElement.addEventListener(it.event, it)
+        }
+    }
+
+    fun updateAttrs(attrs: Map<String, String?>) {
+        val htmlElement = node as? HTMLElement ?: return
+        currentAttrs.forEach {
+            htmlElement.removeAttribute(it.key)
+        }
+        currentAttrs = attrs
+        currentAttrs.forEach {
+            if (it.value != null) htmlElement.setAttribute(it.key, it.value ?: "")
+        }
+    }
+
+    fun updateStyleDeclarations(style: StyleHolder?) {
+        val htmlElement = node as? HTMLElement ?: return
+        // TODO: typed-om-polyfill hasn't StylePropertyMap::clear()
+        htmlElement.style.cssText = ""
+
+        style?.properties?.forEach { (name, value) ->
+            setProperty(htmlElement.attributeStyleMap, name, value)
+        }
+        style?.variables?.forEach { (name, value) ->
+            setVariable(htmlElement.style, name, value)
+        }
+    }
+
+    fun insert(index: Int, nodeWrapper: DomNodeWrapper) {
+        val length = node.childNodes.length
+        if (index < length) {
+            node.insertBefore(nodeWrapper.node, node.childNodes[index]!!)
+        } else {
+            node.appendChild(nodeWrapper.node)
+        }
+    }
+
+    fun remove(index: Int, count: Int) {
+        repeat(count) {
+            node.removeChild(node.childNodes[index]!!)
+        }
+    }
+
+    fun move(from: Int, to: Int, count: Int) {
+        if (from == to) {
+            return // nothing to do
+        }
+
+        for (i in 0 until count) {
+            // if "from" is after "to," the from index moves because we're inserting before it
+            val fromIndex = if (from > to) from + i else from
+            val toIndex = if (from > to) to + i else to + count - 2
+
+            val child = node.removeChild(node.childNodes[fromIndex]!!)
+            node.insertBefore(child, node.childNodes[toIndex]!!)
+        }
+    }
+
+    companion object {
+
+        val UpdateAttrs: DomNodeWrapper.(Map<String, String?>) -> Unit = {
+            this.updateAttrs(it)
+        }
+        val UpdateListeners: DomNodeWrapper.(List<WrappedEventListener<*>>) -> Unit = {
+            this.updateEventListeners(it)
+        }
+        val UpdateProperties: DomNodePropertiesUpdater = {
+            this.updateProperties(it)
+        }
+        val UpdateStyleDeclarations: DomNodeWrapper.(StyleHolder?) -> Unit = {
+            this.updateStyleDeclarations(it)
+        }
+    }
+}
+
+typealias DomNodePropertiesUpdater =
+    DomNodeWrapper.(List<Pair<(HTMLElement, Any) -> Unit, Any>>) -> Unit

web/core/src/jsMain/kotlin/androidx/compose/web/GlobalSnapshotManager.kt

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web
+
+import androidx.compose.runtime.snapshots.ObserverHandle
+import androidx.compose.runtime.snapshots.Snapshot
+import androidx.compose.web.GlobalSnapshotManager.ensureStarted
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.launch
+
+/**
+ * Platform-specific mechanism for starting a monitor of global snapshot state writes
+ * in order to schedule the periodic dispatch of snapshot apply notifications.
+ * This process should remain platform-specific; it is tied to the threading and update model of
+ * a particular platform and framework target.
+ *
+ * Composition bootstrapping mechanisms for a particular platform/framework should call
+ * [ensureStarted] during setup to initialize periodic global snapshot notifications.
+ */
+internal object GlobalSnapshotManager {
+    private var started = false
+    private var commitPending = false
+    private var removeWriteObserver: (ObserverHandle)? = null
+
+    private val scheduleScope = CoroutineScope(JsMicrotasksDispatcher() + SupervisorJob())
+
+    fun ensureStarted() {
+        if (!started) {
+            started = true
+            removeWriteObserver = Snapshot.registerGlobalWriteObserver(globalWriteObserver)
+        }
+    }
+
+    private val globalWriteObserver: (Any) -> Unit = {
+        // Race, but we don't care too much if we end up with multiple calls scheduled.
+        if (!commitPending) {
+            commitPending = true
+            schedule {
+                commitPending = false
+                Snapshot.sendApplyNotifications()
+            }
+        }
+    }
+
+    /**
+     * List of deferred callbacks to run serially. Guarded by its own monitor lock.
+     */
+    private val scheduledCallbacks = mutableListOf<() -> Unit>()
+
+    /**
+     * Guarded by [scheduledCallbacks]'s monitor lock.
+     */
+    private var isSynchronizeScheduled = false
+
+    /**
+     * Synchronously executes any outstanding callbacks and brings snapshots into a
+     * consistent, updated state.
+     */
+    private fun synchronize() {
+        scheduledCallbacks.forEach { it.invoke() }
+        scheduledCallbacks.clear()
+        isSynchronizeScheduled = false
+    }
+
+    private fun schedule(block: () -> Unit) {
+        scheduledCallbacks.add(block)
+        if (!isSynchronizeScheduled) {
+            isSynchronizeScheduled = true
+            scheduleScope.launch { synchronize() }
+        }
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/JsMicrotasksDispatcher.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web
+
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Runnable
+import kotlin.coroutines.CoroutineContext
+import kotlin.js.Promise
+
+internal class JsMicrotasksDispatcher : CoroutineDispatcher() {
+    override fun dispatch(context: CoroutineContext, block: Runnable) {
+        Promise.resolve(Unit).then { block.run() }
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/RenderComposable.kt

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Composition
+import androidx.compose.runtime.ControlledComposition
+import androidx.compose.runtime.DefaultMonotonicFrameClock
+import androidx.compose.runtime.Recomposer
+import androidx.compose.web.elements.DOMScope
+import kotlinx.browser.document
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.CoroutineStart
+import kotlinx.coroutines.launch
+import org.w3c.dom.HTMLBodyElement
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.get
+/**
+ * Use this method to mount the composition at the certain [root]
+ *
+ * @param root - the [HTMLElement] that will be the root of the DOM tree managed by Compose
+ * @param content - the Composable lambda that defines the composition content
+ *
+ * @return the instance of the [Composition]
+ */
+fun <THTMLElement : HTMLElement> renderComposable(
+    root: THTMLElement,
+    content: @Composable DOMScope<THTMLElement>.() -> Unit
+): Composition {
+    GlobalSnapshotManager.ensureStarted()
+
+    val context = DefaultMonotonicFrameClock + JsMicrotasksDispatcher()
+    val recomposer = Recomposer(context)
+    val composition = ControlledComposition(
+        applier = DomApplier(DomNodeWrapper(root)),
+        parent = recomposer
+    )
+    val scope = object : DOMScope<THTMLElement> {}
+    composition.setContent @Composable {
+        content(scope)
+    }
+
+    CoroutineScope(context).launch(start = CoroutineStart.UNDISPATCHED) {
+        recomposer.runRecomposeAndApplyChanges()
+    }
+    return composition
+}
+
+/**
+ * Use this method to mount the composition at the element with id - [rootElementId].
+ *
+ * @param rootElementId - the id of the [HTMLElement] that will be the root of the DOM tree managed
+ * by Compose
+ * @param content - the Composable lambda that defines the composition content
+ *
+ * @return the instance of the [Composition]
+ */
+@Suppress("UNCHECKED_CAST")
+fun renderComposable(
+    rootElementId: String,
+    content: @Composable DOMScope<HTMLElement>.() -> Unit
+): Composition = renderComposable(
+    root = document.getElementById(rootElementId) as HTMLElement,
+    content = content
+)
+
+/**
+ * Use this method to mount the composition at the [HTMLBodyElement] of the current document
+ *
+ * @param content - the Composable lambda that defines the composition content
+ *
+ * @return the instance of the [Composition]
+ */
+fun renderComposableInBody(
+    content: @Composable DOMScope<HTMLBodyElement>.() -> Unit
+): Composition = renderComposable(
+    root = document.getElementsByTagName("body")[0] as HTMLBodyElement,
+    content = content
+)

web/core/src/jsMain/kotlin/androidx/compose/web/attributes/Attrs.kt

@@ -0,0 +1,367 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.attributes
+
+import org.w3c.dom.HTMLInputElement
+
+open class Tag {
+    object Div : Tag()
+    object A : Tag()
+    object Button : Tag()
+    object Form : Tag()
+    object Input : Tag()
+    object Select : Tag()
+    object Option : Tag()
+    object OptGroup : Tag()
+    object H : Tag()
+    object Ul : Tag()
+    object Ol : Tag()
+    object Li : Tag()
+    object Img : Tag()
+    object TextArea : Tag()
+    object Nav : Tag()
+    object Span : Tag()
+    object P : Tag()
+    object Br : Tag()
+    object Style : Tag()
+    object Pre : Tag()
+    object Code : Tag()
+    object Label : Tag()
+    object Table : Tag()
+    object Caption : Tag()
+    object Col : Tag()
+    object Colgroup : Tag()
+    object Tr : Tag()
+    object Thead : Tag()
+    object Th : Tag()
+    object Td : Tag()
+    object Tbody : Tag()
+    object Tfoot : Tag()
+}
+
+/* Anchor <a> attributes */
+
+fun AttrsBuilder<Tag.A>.href(value: String?) =
+    attr("href", value)
+
+fun AttrsBuilder<Tag.A>.target(value: ATarget = ATarget.Self) =
+    attr("target", value.targetStr)
+
+fun AttrsBuilder<Tag.A>.ref(value: ARel) =
+    attr("rel", value.relStr)
+
+fun AttrsBuilder<Tag.A>.ping(value: String) =
+    attr("ping", value)
+
+fun AttrsBuilder<Tag.A>.ping(vararg urls: String) =
+    attr("ping", urls.joinToString(" "))
+
+fun AttrsBuilder<Tag.A>.hreflang(value: String) =
+    attr("hreflang", value)
+
+fun AttrsBuilder<Tag.A>.download(value: String = "") =
+    attr("download", value)
+
+/* Button attributes */
+
+fun AttrsBuilder<Tag.Button>.autoFocus(value: Boolean = true) =
+    attr("autofocus", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Button>.disabled(value: Boolean = true) =
+    attr("disabled", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Button>.form(formId: String) =
+    attr("form", formId)
+
+fun AttrsBuilder<Tag.Button>.formAction(url: String) =
+    attr("formaction", url)
+
+fun AttrsBuilder<Tag.Button>.formEncType(value: ButtonFormEncType) =
+    attr("formenctype", value.typeStr)
+
+fun AttrsBuilder<Tag.Button>.formMethod(value: ButtonFormMethod) =
+    attr("formmethod", value.methodStr)
+
+fun AttrsBuilder<Tag.Button>.formNoValidate(value: Boolean = true) =
+    attr("formnovalidate", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Button>.formTarget(value: ButtonFormTarget) =
+    attr("formtarget", value.targetStr)
+
+fun AttrsBuilder<Tag.Button>.name(value: String) =
+    attr("name", value)
+
+fun AttrsBuilder<Tag.Button>.type(value: ButtonType) =
+    attr("type", value.str)
+
+fun AttrsBuilder<Tag.Button>.value(value: String) =
+    attr("value", value)
+
+/* Form attributes */
+
+fun AttrsBuilder<Tag.Form>.action(value: String) =
+    attr("action", value)
+
+fun AttrsBuilder<Tag.Form>.acceptCharset(value: String) =
+    attr("accept-charset", value)
+
+fun AttrsBuilder<Tag.Form>.autoComplete(value: Boolean) =
+    attr("autocomplete", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Form>.encType(value: FormEncType) =
+    attr("enctype", value.typeStr)
+
+fun AttrsBuilder<Tag.Form>.method(value: FormMethod) =
+    attr("method", value.methodStr)
+
+fun AttrsBuilder<Tag.Form>.noValidate(value: Boolean = true) =
+    attr("novalidate", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Form>.target(value: FormTarget) =
+    attr("target", value.targetStr)
+
+/* Input attributes */
+
+fun AttrsBuilder<Tag.Input>.type(value: InputType) =
+    attr("type", value.typeStr)
+
+fun AttrsBuilder<Tag.Input>.accept(value: String) =
+    attr("accept", value) // type: file only
+
+fun AttrsBuilder<Tag.Input>.alt(value: String) =
+    attr("alt", value) // type: image only
+
+fun AttrsBuilder<Tag.Input>.autoComplete(value: Boolean = true) =
+    attr("autocomplete", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Input>.autoFocus(value: Boolean = true) =
+    attr("autofocus", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Input>.capture(value: String) =
+    attr("capture", value) // type: file only
+
+fun AttrsBuilder<Tag.Input>.checked(value: Boolean = true) =
+    attr("checked", if (value) "" else null) // radio, checkbox
+
+fun AttrsBuilder<Tag.Input>.dirName(value: String) =
+    attr("dirname", value) // text, search
+
+fun AttrsBuilder<Tag.Input>.disabled(value: Boolean = true) =
+    attr("disabled", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Input>.form(id: String) =
+    attr("form", id)
+
+fun AttrsBuilder<Tag.Input>.formAction(url: String) =
+    attr("formaction", url)
+
+fun AttrsBuilder<Tag.Input>.formEncType(value: InputFormEncType) =
+    attr("formenctype", value.typeStr)
+
+fun AttrsBuilder<Tag.Input>.formMethod(value: InputFormMethod) =
+    attr("formmethod", value.methodStr)
+
+fun AttrsBuilder<Tag.Input>.formNoValidate(value: Boolean = true) =
+    attr("formnovalidate", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Input>.formTarget(value: InputFormTarget) =
+    attr("formtarget", value.targetStr)
+
+fun AttrsBuilder<Tag.Input>.height(value: Int) =
+    attr("height", value.toString()) // image only
+
+fun AttrsBuilder<Tag.Input>.width(value: Int) =
+    attr("width", value.toString()) // image only
+
+fun AttrsBuilder<Tag.Input>.list(dataListId: String) =
+    attr("list", dataListId)
+
+fun AttrsBuilder<Tag.Input>.max(value: String) =
+    attr("max", value)
+
+fun AttrsBuilder<Tag.Input>.maxLength(value: Int) =
+    attr("maxlength", value.toString())
+
+fun AttrsBuilder<Tag.Input>.min(value: String) =
+    attr("min", value)
+
+fun AttrsBuilder<Tag.Input>.minLength(value: Int) =
+    attr("minlength", value.toString())
+
+fun AttrsBuilder<Tag.Input>.multiple(value: Boolean = true) =
+    attr("multiple", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Input>.name(value: String) =
+    attr("name", value)
+
+fun AttrsBuilder<Tag.Input>.pattern(value: String) =
+    attr("pattern", value)
+
+fun AttrsBuilder<Tag.Input>.placeholder(value: String) =
+    attr("placeholder", value)
+
+fun AttrsBuilder<Tag.Input>.readOnly(value: Boolean = true) =
+    attr("readonly", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Input>.required(value: Boolean = true) =
+    attr("required", value.toString())
+
+fun AttrsBuilder<Tag.Input>.size(value: Int) =
+    attr("size", value.toString())
+
+fun AttrsBuilder<Tag.Input>.src(value: String) =
+    attr("src", value.toString()) // image only
+
+fun AttrsBuilder<Tag.Input>.step(value: Int) =
+    attr("step", value.toString()) // numeric types only
+
+fun AttrsBuilder<Tag.Input>.valueAttr(value: String) =
+    attr("value", value)
+
+fun AttrsBuilder<Tag.Input>.value(value: String): AttrsBuilder<Tag.Input> {
+    prop(setInputValue, value)
+    return this
+}
+
+/* Option attributes */
+
+fun AttrsBuilder<Tag.Option>.value(value: String) =
+    attr("value", value)
+
+fun AttrsBuilder<Tag.Option>.disabled(value: Boolean = true) =
+    attr("disabled", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Option>.selected(value: Boolean = true) =
+    attr("selected", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Option>.label(value: String) =
+    attr("label", value)
+
+/* Select attributes */
+
+fun AttrsBuilder<Tag.Select>.autocomplete(value: String) =
+    attr("autocomplete", value)
+
+fun AttrsBuilder<Tag.Select>.autofocus(value: Boolean = true) =
+    attr("autofocus", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Select>.disabled(value: Boolean = true) =
+    attr("disabled", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Select>.form(formId: String) =
+    attr("form", formId)
+
+fun AttrsBuilder<Tag.Select>.multiple(value: Boolean = true) =
+    attr("multiple", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Select>.name(value: String) =
+    attr("name", value)
+
+fun AttrsBuilder<Tag.Select>.required(value: Boolean = true) =
+    attr("required", if (value) "" else null)
+
+fun AttrsBuilder<Tag.Select>.size(numberOfRows: Int) =
+    attr("size", numberOfRows.toString())
+
+/* OptGroup attributes */
+
+fun AttrsBuilder<Tag.OptGroup>.label(value: String) =
+    attr("label", value)
+
+fun AttrsBuilder<Tag.OptGroup>.disabled(value: Boolean = true) =
+    attr("disabled", if (value) "" else null)
+
+/* TextArea attributes */
+
+fun AttrsBuilder<Tag.TextArea>.autoComplete(value: Boolean = true) =
+    attr("autocomplete", if (value) "on" else "off")
+
+fun AttrsBuilder<Tag.TextArea>.autoFocus(value: Boolean = true) =
+    attr("autofocus", if (value) "" else null)
+
+fun AttrsBuilder<Tag.TextArea>.cols(value: Int) =
+    attr("cols", value.toString())
+
+fun AttrsBuilder<Tag.TextArea>.disabled(value: Boolean = true) =
+    attr("disabled", if (value) "" else null)
+
+fun AttrsBuilder<Tag.TextArea>.form(formId: String) =
+    attr("form", formId)
+
+fun AttrsBuilder<Tag.TextArea>.maxLength(value: Int) =
+    attr("maxlength", value.toString())
+
+fun AttrsBuilder<Tag.TextArea>.minLength(value: Int) =
+    attr("minlength", value.toString())
+
+fun AttrsBuilder<Tag.TextArea>.name(value: String) =
+    attr("name", value)
+
+fun AttrsBuilder<Tag.TextArea>.placeholder(value: String) =
+    attr("placeholder", value)
+
+fun AttrsBuilder<Tag.TextArea>.readOnly(value: Boolean = true) =
+    attr("readonly", if (value) "" else null)
+
+fun AttrsBuilder<Tag.TextArea>.required(value: Boolean = true) =
+    attr("required", if (value) "" else null)
+
+fun AttrsBuilder<Tag.TextArea>.rows(value: Int) =
+    attr("rows", value.toString())
+
+fun AttrsBuilder<Tag.TextArea>.wrap(value: TextAreaWrap) =
+    attr("wrap", value.str)
+
+fun AttrsBuilder<Tag.TextArea>.value(value: String): AttrsBuilder<Tag.TextArea> {
+    prop(setInputValue, value)
+    return this
+}
+
+/* Img attributes */
+
+fun AttrsBuilder<Tag.Img>.src(value: String?): AttrsBuilder<Tag.Img> =
+    attr("src", value)
+
+fun AttrsBuilder<Tag.Img>.alt(value: String?): AttrsBuilder<Tag.Img> =
+    attr("alt", value)
+
+private val setInputValue: (HTMLInputElement, String) -> Unit = { e, v ->
+    e.value = v
+}
+
+/* Img attributes */
+fun AttrsBuilder<Tag.Label>.forId(value: String?): AttrsBuilder<Tag.Label> =
+    attr("for", value)
+
+/* Table attributes */
+fun AttrsBuilder<Tag.Th>.scope(value: Scope?): AttrsBuilder<Tag.Th> =
+    attr("scope", value?.str)
+
+fun AttrsBuilder<Tag.Col>.span(value: Int): AttrsBuilder<Tag.Col> =
+    attr("span", value.toString())
+
+fun AttrsBuilder<Tag.Th>.colspan(value: Int): AttrsBuilder<Tag.Th> =
+    attr("colspan", value.toString())
+
+fun AttrsBuilder<Tag.Th>.rowspan(value: Int): AttrsBuilder<Tag.Th> =
+    attr("rowspan", value.toString())
+
+fun AttrsBuilder<Tag.Td>.colspan(value: Int): AttrsBuilder<Tag.Td> =
+    attr("colspan", value.toString())
+
+fun AttrsBuilder<Tag.Td>.rowspan(value: Int): AttrsBuilder<Tag.Td> =
+    attr("rowspan", value.toString())

web/core/src/jsMain/kotlin/androidx/compose/web/attributes/AttrsBuilder.kt

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.attributes
+
+import androidx.compose.runtime.DisposableEffectResult
+import androidx.compose.runtime.DisposableEffectScope
+import org.w3c.dom.HTMLElement
+
+class AttrsBuilder<TTag : Tag> : EventsListenerBuilder() {
+    private val map = mutableMapOf<String, String>()
+
+    val propertyUpdates = mutableListOf<Pair<(HTMLElement, Any) -> Unit, Any>>()
+    var refEffect: (DisposableEffectScope.(HTMLElement) -> DisposableEffectResult)? = null
+
+    inline fun classes(builder: ClassesAttrBuilder.() -> Unit) =
+        prop(setClassList, ClassesAttrBuilder().apply(builder).asList().toTypedArray())
+
+    fun classes(vararg classes: String) = prop(setClassList, classes)
+
+    fun id(value: String) = attr(ID, value)
+    fun hidden(value: Boolean) = attr(HIDDEN, value.toString())
+    fun title(value: String) = attr(TITLE, value)
+    fun dir(value: DirType) = attr(DIR, value.dirStr)
+    fun draggable(value: Draggable) = attr(DRAGGABLE, value.str)
+    fun contentEditable(value: Boolean) = attr(CONTENT_EDITABLE, value.toString())
+    fun lang(value: String) = attr(LANG, value)
+    fun tabIndex(value: Int) = attr(TAB_INDEX, value.toString())
+    fun spellCheck(value: Boolean) = attr(SPELLCHECK, value.toString())
+
+    fun ref(effect: DisposableEffectScope.(HTMLElement) -> DisposableEffectResult) {
+        this.refEffect = effect
+    }
+
+    fun attr(attr: String, value: String?): AttrsBuilder<TTag> {
+        if (value == null && attr in map) {
+            map.remove(attr)
+        } else if (value != null) {
+            map[attr] = value
+        }
+
+        return this
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    fun <E : HTMLElement, V : Any> prop(update: (E, V) -> Unit, value: V) {
+        propertyUpdates.add((update to value) as Pair<(HTMLElement, Any) -> Unit, Any>)
+    }
+
+    fun collect(): Map<String, String> {
+        return map
+    }
+
+    companion object {
+        const val CLASS = "class"
+        const val ID = "id"
+        const val HIDDEN = "hidden"
+        const val TITLE = "title"
+        const val DIR = "dir"
+        const val DRAGGABLE = "draggable"
+        const val CONTENT_EDITABLE = "contenteditable"
+        const val LANG = "lang"
+        const val TAB_INDEX = "tabindex"
+        const val SPELLCHECK = "spellcheck"
+    }
+}
+
+class ClassesAttrBuilder {
+    private val classes = mutableListOf<String>()
+
+    operator fun String.unaryPlus() {
+        classes.add(this)
+    }
+
+    fun asList(): List<String> = classes
+    fun asString(): String = classes.joinToString(" ")
+}
+
+val setClassList: (HTMLElement, Array<out String>) -> Unit = { e, classList ->
+    e.className = ""
+    e.classList.add(*classList)
+}

web/core/src/jsMain/kotlin/androidx/compose/web/attributes/EventsListenerBuilder.kt

@@ -0,0 +1,293 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.attributes
+
+import androidx.compose.web.events.WrappedCheckBoxInputEvent
+import androidx.compose.web.events.WrappedClipboardEvent
+import androidx.compose.web.events.WrappedDragEvent
+import androidx.compose.web.events.WrappedEvent
+import androidx.compose.web.events.WrappedFocusEvent
+import androidx.compose.web.events.WrappedInputEvent
+import androidx.compose.web.events.WrappedKeyboardEvent
+import androidx.compose.web.events.WrappedMouseEvent
+import androidx.compose.web.events.WrappedRadioInputEvent
+import androidx.compose.web.events.WrappedTextInputEvent
+import androidx.compose.web.events.WrappedTouchEvent
+import androidx.compose.web.events.WrappedWheelEvent
+import androidx.compose.web.events.GenericWrappedEvent
+
+open class EventsListenerBuilder {
+
+    private val listeners = mutableListOf<WrappedEventListener<*>>()
+
+    fun onCopy(options: Options = Options.DEFAULT, listener: (WrappedClipboardEvent) -> Unit) {
+        listeners.add(ClipboardEventListener(COPY, options, listener))
+    }
+
+    fun onCut(options: Options = Options.DEFAULT, listener: (WrappedClipboardEvent) -> Unit) {
+        listeners.add(ClipboardEventListener(CUT, options, listener))
+    }
+
+    fun onPaste(options: Options = Options.DEFAULT, listener: (WrappedClipboardEvent) -> Unit) {
+        listeners.add(ClipboardEventListener(PASTE, options, listener))
+    }
+
+    fun onContextMenu(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(CONTEXTMENU, options, listener))
+    }
+
+    fun onClick(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(CLICK, options, listener))
+    }
+
+    fun onDoubleClick(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(DBLCLICK, options, listener))
+    }
+
+    fun onInput(options: Options = Options.DEFAULT, listener: (WrappedInputEvent) -> Unit) {
+        listeners.add(InputEventListener(INPUT, options, listener))
+    }
+
+    fun onTextInput(options: Options = Options.DEFAULT, listener: (WrappedTextInputEvent) -> Unit) {
+        listeners.add(TextInputEventListener(options, listener))
+    }
+
+    fun onCheckboxInput(
+        options: Options = Options.DEFAULT,
+        listener: (WrappedCheckBoxInputEvent) -> Unit
+    ) {
+        listeners.add(CheckBoxInputEventListener(options, listener))
+    }
+
+    fun onRadioInput(
+        options: Options = Options.DEFAULT,
+        listener: (WrappedRadioInputEvent) -> Unit
+    ) {
+        listeners.add(RadioInputEventListener(options, listener))
+    }
+
+    fun onRangeInput(
+        options: Options = Options.DEFAULT,
+        listener: (GenericWrappedEvent<*>) -> Unit
+    ) {
+        listeners.add(WrappedEventListener(INPUT, options, listener))
+    }
+
+    fun onGenericInput(
+        options: Options = Options.DEFAULT,
+        listener: (GenericWrappedEvent<*>) -> Unit
+    ) {
+        listeners.add(WrappedEventListener(INPUT, options, listener))
+    }
+
+    fun onChange(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(CHANGE, options, listener))
+    }
+
+    fun onInvalid(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(INVALID, options, listener))
+    }
+
+    fun onSearch(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(SEARCH, options, listener))
+    }
+
+    fun onFocus(options: Options = Options.DEFAULT, listener: (WrappedFocusEvent) -> Unit) {
+        listeners.add(FocusEventListener(FOCUS, options, listener))
+    }
+
+    fun onBlur(options: Options = Options.DEFAULT, listener: (WrappedFocusEvent) -> Unit) {
+        listeners.add(FocusEventListener(BLUR, options, listener))
+    }
+
+    fun onFocusIn(options: Options = Options.DEFAULT, listener: (WrappedFocusEvent) -> Unit) {
+        listeners.add(FocusEventListener(FOCUSIN, options, listener))
+    }
+
+    fun onFocusOut(options: Options = Options.DEFAULT, listener: (WrappedFocusEvent) -> Unit) {
+        listeners.add(FocusEventListener(FOCUSOUT, options, listener))
+    }
+
+    fun onKeyDown(options: Options = Options.DEFAULT, listener: (WrappedKeyboardEvent) -> Unit) {
+        listeners.add(KeyboardEventListener(KEYDOWN, options, listener))
+    }
+
+    fun onKeyUp(options: Options = Options.DEFAULT, listener: (WrappedKeyboardEvent) -> Unit) {
+        listeners.add(KeyboardEventListener(KEYUP, options, listener))
+    }
+
+    fun onMouseDown(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSEDOWN, options, listener))
+    }
+
+    fun onMouseUp(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSEUP, options, listener))
+    }
+
+    fun onMouseEnter(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSEENTER, options, listener))
+    }
+
+    fun onMouseLeave(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSELEAVE, options, listener))
+    }
+
+    fun onMouseMove(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSEMOVE, options, listener))
+    }
+
+    fun onMouseOut(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSEOUT, options, listener))
+    }
+
+    fun onMouseOver(options: Options = Options.DEFAULT, listener: (WrappedMouseEvent) -> Unit) {
+        listeners.add(MouseEventListener(MOUSEOVER, options, listener))
+    }
+
+    fun onWheel(options: Options = Options.DEFAULT, listener: (WrappedWheelEvent) -> Unit) {
+        listeners.add(MouseWheelEventListener(WHEEL, options, listener))
+    }
+
+    fun onScroll(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(SCROLL, options, listener))
+    }
+
+    fun onSelect(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(SELECT, options, listener))
+    }
+
+    fun onTouchCancel(options: Options = Options.DEFAULT, listener: (WrappedTouchEvent) -> Unit) {
+        listeners.add(TouchEventListener(TOUCHCANCEL, options, listener))
+    }
+
+    fun onTouchMove(options: Options = Options.DEFAULT, listener: (WrappedTouchEvent) -> Unit) {
+        listeners.add(TouchEventListener(TOUCHMOVE, options, listener))
+    }
+
+    fun onTouchEnd(options: Options = Options.DEFAULT, listener: (WrappedTouchEvent) -> Unit) {
+        listeners.add(TouchEventListener(TOUCHEND, options, listener))
+    }
+
+    fun onTouchStart(options: Options = Options.DEFAULT, listener: (WrappedTouchEvent) -> Unit) {
+        listeners.add(TouchEventListener(TOUCHSTART, options, listener))
+    }
+
+    fun onAnimationEnd(options: Options = Options.DEFAULT, listener: (WrappedTouchEvent) -> Unit) {
+        listeners.add(WrappedEventListener(ANIMATIONEND, options, listener))
+    }
+
+    fun onAnimationIteration(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(ANIMATIONITERATION, options, listener))
+    }
+
+    fun onAnimationStart(options: Options = Options.DEFAULT, listener: (WrappedEvent) -> Unit) {
+        listeners.add(WrappedEventListener(ANIMATIONSTART, options, listener))
+    }
+
+    fun onBeforeInput(options: Options = Options.DEFAULT, listener: (WrappedInputEvent) -> Unit) {
+        listeners.add(InputEventListener(BEFOREINPUT, options, listener))
+    }
+
+    fun onDrag(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DRAG, options, listener))
+    }
+
+    fun onDrop(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DROP, options, listener))
+    }
+
+    fun onDragStart(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DRAGSTART, options, listener))
+    }
+
+    fun onDragEnd(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DRAGEND, options, listener))
+    }
+
+    fun onDragOver(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DRAGOVER, options, listener))
+    }
+
+    fun onDragEnter(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DRAGENTER, options, listener))
+    }
+
+    fun onDragLeave(options: Options = Options.DEFAULT, listener: (WrappedDragEvent) -> Unit) {
+        listeners.add(DragEventListener(DRAGLEAVE, options, listener))
+    }
+
+    fun asList(): List<WrappedEventListener<*>> = listeners
+
+    fun addEventListener(
+        eventName: String,
+        options: Options = Options.DEFAULT,
+        listener: (WrappedEvent) -> Unit
+    ) {
+        listeners.add(WrappedEventListener(eventName, options, listener))
+    }
+
+    companion object {
+        const val COPY = "copy"
+        const val CUT = "cut"
+        const val PASTE = "paste"
+        const val CONTEXTMENU = "contextmenu"
+
+        const val CLICK = "click"
+        const val DBLCLICK = "dblclick"
+        const val FOCUS = "focus"
+        const val BLUR = "blur"
+        const val FOCUSIN = "focusin"
+        const val FOCUSOUT = "focusout"
+
+        const val KEYDOWN = "keydown"
+        const val KEYUP = "keyup"
+        const val MOUSEDOWN = "mousedown"
+        const val MOUSEUP = "mouseup"
+        const val MOUSEENTER = "mouseenter"
+        const val MOUSELEAVE = "mouseleave"
+        const val MOUSEMOVE = "mousemove"
+        const val MOUSEOUT = "mouseout"
+        const val MOUSEOVER = "mouseover"
+        const val WHEEL = "wheel"
+        const val SCROLL = "scroll"
+        const val SELECT = "select"
+
+        const val TOUCHCANCEL = "touchcancel"
+        const val TOUCHEND = "touchend"
+        const val TOUCHMOVE = "touchmove"
+        const val TOUCHSTART = "touchstart"
+
+        const val ANIMATIONCANCEL = "animationcancel" // firefox and safari only
+        const val ANIMATIONEND = "animationend"
+        const val ANIMATIONITERATION = "animationiteration"
+        const val ANIMATIONSTART = "animationstart"
+
+        const val BEFOREINPUT = "beforeinput"
+        const val INPUT = "input"
+        const val CHANGE = "change"
+        const val INVALID = "invalid"
+        const val SEARCH = "search"
+
+        const val DRAG = "drag"
+        const val DROP = "drop"
+        const val DRAGSTART = "dragstart"
+        const val DRAGEND = "dragend"
+        const val DRAGOVER = "dragover"
+        const val DRAGENTER = "dragenter"
+        const val DRAGLEAVE = "dragleave"
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/attributes/PredefinedAttrValues.kt

@@ -0,0 +1,150 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.attributes
+
+sealed class InputType(val typeStr: String) {
+    object Button : InputType("button")
+    object Checkbox : InputType("checkbox")
+    object Color : InputType("color")
+    object Date : InputType("date")
+    object DateTimeLocal : InputType("datetime-local")
+    object Email : InputType("email")
+    object File : InputType("file")
+    object Hidden : InputType("hidden")
+    object Month : InputType("month")
+    object Number : InputType("number")
+    object Password : InputType("password")
+    object Radio : InputType("radio")
+    object Range : InputType("range")
+    object Search : InputType("search")
+    object Submit : InputType("submit")
+    object Tel : InputType("tel")
+    object Text : InputType("text")
+    object Time : InputType("time")
+    object Url : InputType("url")
+    object Week : InputType("week")
+}
+
+sealed class DirType(val dirStr: String) {
+    object Ltr : DirType("ltr")
+    object Rtl : DirType("rtl")
+    object Auto : DirType("auto")
+}
+
+sealed class ATarget(val targetStr: String) {
+    object Blank : ATarget("_blank")
+    object Parent : ATarget("_parent")
+    object Self : ATarget("_self")
+    object Top : ATarget("_top")
+}
+
+sealed class ARel(val relStr: String) {
+    object Alternate : ARel("alternate")
+    object Author : ARel("author")
+    object Bookmark : ARel("bookmark")
+    object External : ARel("external")
+    object Help : ARel("help")
+    object License : ARel("license")
+    object Next : ARel("next")
+    object First : ARel("first")
+    object Prev : ARel("prev")
+    object Last : ARel("last")
+    object NoFollow : ARel("nofollow")
+    object NoOpener : ARel("noopener")
+    object NoReferrer : ARel("noreferrer")
+    object Opener : ARel("opener")
+    object Search : ARel("search")
+    object Tag : ARel("tag")
+
+    class CustomARel(value: String) : ARel(value)
+}
+
+enum class Draggable(val str: String) {
+    True("true"), False("false"), Auto("auto");
+}
+
+enum class ButtonType(val str: String) {
+    Button("button"), Reset("reset"), Submit("submit")
+}
+
+sealed class ButtonFormTarget(val targetStr: String) {
+    object Blank : ButtonFormTarget("_blank")
+    object Parent : ButtonFormTarget("_parent")
+    object Self : ButtonFormTarget("_self")
+    object Top : ButtonFormTarget("_top")
+}
+
+enum class ButtonFormMethod(val methodStr: String) {
+    Get("get"), Post("post")
+}
+
+enum class ButtonFormEncType(val typeStr: String) {
+    MultipartFormData("multipart/form-data"),
+    ApplicationXWwwFormUrlEncoded("application/x-www-form-urlencoded"),
+    TextPlain("text/plain")
+}
+
+enum class FormEncType(val typeStr: String) {
+    MultipartFormData("multipart/form-data"),
+    ApplicationXWwwFormUrlEncoded("application/x-www-form-urlencoded"),
+    TextPlain("text/plain")
+}
+
+enum class FormMethod(val methodStr: String) {
+    Get("get"),
+    Post("post"),
+    Dialog("dialog")
+}
+
+sealed class FormTarget(val targetStr: String) {
+    object Blank : FormTarget("_blank")
+    object Parent : FormTarget("_parent")
+    object Self : FormTarget("_self")
+    object Top : FormTarget("_top")
+}
+
+enum class InputFormEncType(val typeStr: String) {
+    MultipartFormData("multipart/form-data"),
+    ApplicationXWwwFormUrlEncoded("application/x-www-form-urlencoded"),
+    TextPlain("text/plain")
+}
+
+enum class InputFormMethod(val methodStr: String) {
+    Get("get"),
+    Post("post"),
+    Dialog("dialog")
+}
+
+sealed class InputFormTarget(val targetStr: String) {
+    object Blank : InputFormTarget("_blank")
+    object Parent : InputFormTarget("_parent")
+    object Self : InputFormTarget("_self")
+    object Top : InputFormTarget("_top")
+}
+
+enum class TextAreaWrap(val str: String) {
+    Hard("hard"),
+    Soft("soft"),
+    Off("off")
+}
+
+enum class Scope(val str: String) {
+    Row("row"),
+    Rowgroup("rowgroup"),
+    Col("col"),
+    Colgroup("colgroup")
+}

web/core/src/jsMain/kotlin/androidx/compose/web/attributes/WrappedEventListener.kt

@@ -0,0 +1,184 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.attributes
+
+import androidx.compose.web.events.GenericWrappedEvent
+import androidx.compose.web.events.WrappedCheckBoxInputEvent
+import androidx.compose.web.events.WrappedClipboardEvent
+import androidx.compose.web.events.WrappedDragEvent
+import androidx.compose.web.events.WrappedEventImpl
+import androidx.compose.web.events.WrappedFocusEvent
+import androidx.compose.web.events.WrappedInputEvent
+import androidx.compose.web.events.WrappedKeyboardEvent
+import androidx.compose.web.events.WrappedMouseEvent
+import androidx.compose.web.events.WrappedPointerEvent
+import androidx.compose.web.events.WrappedRadioInputEvent
+import androidx.compose.web.events.WrappedTextInputEvent
+import androidx.compose.web.events.WrappedTouchEvent
+import androidx.compose.web.events.WrappedWheelEvent
+import org.w3c.dom.DragEvent
+import org.w3c.dom.TouchEvent
+import org.w3c.dom.clipboard.ClipboardEvent
+import org.w3c.dom.events.Event
+import org.w3c.dom.events.FocusEvent
+import org.w3c.dom.events.InputEvent
+import org.w3c.dom.events.KeyboardEvent
+import org.w3c.dom.events.MouseEvent
+import org.w3c.dom.events.WheelEvent
+import org.w3c.dom.pointerevents.PointerEvent
+
+open class WrappedEventListener<T : GenericWrappedEvent<*>>(
+    val event: String,
+    val options: Options,
+    val listener: (T) -> Unit
+) : org.w3c.dom.events.EventListener {
+
+    @Suppress("UNCHECKED_CAST")
+    override fun handleEvent(event: Event) {
+        listener(WrappedEventImpl(event) as T)
+    }
+}
+
+class Options {
+    // TODO: add options for addEventListener
+
+    companion object {
+        val DEFAULT = Options()
+    }
+}
+
+internal class MouseEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedMouseEvent) -> Unit
+) : WrappedEventListener<WrappedMouseEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedMouseEvent(event as MouseEvent))
+    }
+}
+
+internal class MouseWheelEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedWheelEvent) -> Unit
+) : WrappedEventListener<WrappedWheelEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedWheelEvent(event as WheelEvent))
+    }
+}
+
+internal class KeyboardEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedKeyboardEvent) -> Unit
+) : WrappedEventListener<WrappedKeyboardEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedKeyboardEvent(event as KeyboardEvent))
+    }
+}
+
+internal class FocusEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedFocusEvent) -> Unit
+) : WrappedEventListener<WrappedFocusEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedFocusEvent(event as FocusEvent))
+    }
+}
+
+internal class TouchEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedTouchEvent) -> Unit
+) : WrappedEventListener<WrappedTouchEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedTouchEvent(event as TouchEvent))
+    }
+}
+
+internal class DragEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedDragEvent) -> Unit
+) : WrappedEventListener<WrappedDragEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedDragEvent(event as DragEvent))
+    }
+}
+
+internal class PointerEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedPointerEvent) -> Unit
+) : WrappedEventListener<WrappedPointerEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedPointerEvent(event as PointerEvent))
+    }
+}
+
+internal class ClipboardEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedClipboardEvent) -> Unit
+) : WrappedEventListener<WrappedClipboardEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedClipboardEvent(event as ClipboardEvent))
+    }
+}
+
+internal class InputEventListener(
+    event: String,
+    options: Options,
+    listener: (WrappedInputEvent) -> Unit
+) : WrappedEventListener<WrappedInputEvent>(event, options, listener) {
+    override fun handleEvent(event: Event) {
+        listener(WrappedInputEvent(event as InputEvent))
+    }
+}
+
+internal class RadioInputEventListener(
+    options: Options,
+    listener: (WrappedRadioInputEvent) -> Unit
+) : WrappedEventListener<WrappedRadioInputEvent>(EventsListenerBuilder.INPUT, options, listener) {
+    override fun handleEvent(event: Event) {
+        val checked = event.target.asDynamic().checked as Boolean
+        listener(WrappedRadioInputEvent(event, checked))
+    }
+}
+
+internal class CheckBoxInputEventListener(
+    options: Options,
+    listener: (WrappedCheckBoxInputEvent) -> Unit
+) : WrappedEventListener<WrappedCheckBoxInputEvent>(
+    EventsListenerBuilder.INPUT, options, listener
+) {
+    override fun handleEvent(event: Event) {
+        val checked = event.target.asDynamic().checked as Boolean
+        listener(WrappedCheckBoxInputEvent(event, checked))
+    }
+}
+
+internal class TextInputEventListener(
+    options: Options,
+    listener: (WrappedTextInputEvent) -> Unit
+) : WrappedEventListener<WrappedTextInputEvent>(EventsListenerBuilder.INPUT, options, listener) {
+    override fun handleEvent(event: Event) {
+        val text = event.target.asDynamic().value as String
+        listener(WrappedTextInputEvent(event as InputEvent, text))
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSS.kt

@@ -0,0 +1,450 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@file:Suppress("UNUSED")
+
+package androidx.compose.web.css
+
+import kotlinx.browser.window
+import org.w3c.dom.DOMMatrix
+import org.w3c.dom.DOMMatrixReadOnly
+import org.w3c.dom.Element
+import org.w3c.dom.css.CSSRule
+import org.w3c.dom.css.CSSRuleList
+import org.w3c.dom.css.CSSStyleRule
+import org.w3c.dom.css.ElementCSSInlineStyle
+import org.w3c.dom.css.StyleSheet
+
+inline val StyleSheet.cssRules
+    get() = this.asDynamic().cssRules.unsafeCast<CSSRuleList>()
+
+inline fun StyleSheet.deleteRule(index: Int) {
+    this.asDynamic().deleteRule(index)
+}
+
+inline val CSSStyleRule.styleMap
+    get() = this.asDynamic().styleMap.unsafeCast<StylePropertyMap>()
+
+inline operator fun CSSRuleList.get(index: Int): CSSRule {
+    return this.asDynamic()[index].unsafeCast<CSSRule>()
+}
+
+fun StyleSheet.insertRule(cssRule: String, index: Int? = null): Int {
+    return if (index != null) {
+        this.asDynamic().insertRule(cssRule, index).unsafeCast<Int>()
+    } else {
+        this.asDynamic().insertRule(cssRule).unsafeCast<Int>()
+    }
+}
+
+val ElementCSSInlineStyle.attributeStyleMap
+    get() = this.asDynamic().attributeStyleMap.unsafeCast<StylePropertyMap>()
+
+external interface CSSStyleValue {
+    // toString() : string
+}
+
+@JsName("CSSStyleValue")
+open external class CSSStyleValueJS : CSSStyleValue {
+    companion object {
+        fun parse(property: String, cssText: String): CSSStyleValue
+        fun parseAll(property: String, cssText: String): Array<CSSStyleValue>
+    }
+}
+
+external class CSSVariableReferenceValue(
+    variable: String,
+    fallback: CSSUnparsedValue? = definedExternally
+) {
+    val variable: String
+    val fallback: CSSUnparsedValue?
+}
+
+// type CSSUnparsedSegment = String | CSSVariableReferenceValue
+interface CSSUnparsedSegment {
+    companion object {
+        operator fun invoke(value: String) = value.unsafeCast<CSSUnparsedSegment>()
+        operator fun invoke(value: CSSVariableReferenceValue) =
+            value.unsafeCast<CSSUnparsedSegment>()
+    }
+}
+
+fun CSSUnparsedSegment.asString() = this.asDynamic() as? String
+fun CSSUnparsedSegment.asCSSVariableReferenceValue() =
+    this.asDynamic() as? CSSVariableReferenceValue
+
+external class CSSUnparsedValue(members: Array<CSSUnparsedSegment>) : CSSStyleValue {
+    // TODO: [Symbol.iterator]() : IterableIterator<CSSUnparsedSegment>
+    fun forEach(handler: (CSSUnparsedSegment) -> Unit)
+    val length: Int
+
+    // readonly [index: number]: CSSUnparsedSegment
+    operator fun get(index: Int): CSSUnparsedSegment
+    operator fun set(index: Int, value: CSSUnparsedSegment)
+}
+
+external interface CSSKeywordValue : CSSStyleValue {
+    val value: String
+}
+
+@JsName("CSSKeywordValue")
+external class CSSKeywordValueJS(value: String) : CSSKeywordValue {
+    override val value: String
+}
+
+// type CSSNumberish = number | CSSNumericValue
+interface CSSNumberish {
+    companion object {
+        operator fun invoke(value: Number) = value.unsafeCast<CSSNumberish>()
+        operator fun invoke(value: CSSNumericValue) =
+            value.unsafeCast<CSSNumberish>()
+    }
+}
+
+fun CSSNumberish.asNumber() = this.asDynamic() as? Number
+fun CSSNumberish.asCSSNumericValue(): CSSNumericValue? = this.asDynamic() as? CSSNumericValueJS
+
+// declare enum CSSNumericBaseType {
+//     'length',
+//     'angle',
+//     'time',
+//     'frequency',
+//     'resolution',
+//     'flex',
+//     'percent',
+// }
+enum class CSSNumericBaseType(val value: String) {
+    @JsName("_length")
+    length("length"),
+    angle("angle"),
+    time("time"),
+    frequency("frequency"),
+    resolution("resolution"),
+    flex("flex"),
+    percent("percent")
+}
+
+external interface CSSNumericType {
+    val length: Number
+    val angle: Number
+    val time: Number
+    val frequency: Number
+    val resolution: Number
+    val flex: Number
+    val percent: Number
+    // percentHint: CSSNumericBaseType
+}
+
+val CSSNumericType.percentHint
+    get() = CSSNumericBaseType.valueOf(this.asDynamic().percentHint)
+//    set(value) { this.asDynamic().percentHint = value.value }
+
+external interface CSSNumericValue : CSSStyleValue {
+    fun add(vararg values: CSSNumberish): CSSNumericValue
+    fun sub(vararg values: CSSNumberish): CSSNumericValue
+    fun mul(vararg values: CSSNumberish): CSSNumericValue
+    fun div(vararg values: CSSNumberish): CSSNumericValue
+    fun min(vararg values: CSSNumberish): CSSNumericValue
+    fun max(vararg values: CSSNumberish): CSSNumericValue
+
+    fun equals(vararg values: CSSNumberish): Boolean
+
+    fun to(unit: String): CSSUnitValue
+    fun toSum(vararg units: String): CSSMathSum
+    fun type(): CSSNumericType
+}
+
+abstract external class CSSNumericValueJS : CSSNumericValue {
+    override fun add(vararg values: CSSNumberish): CSSNumericValue
+    override fun sub(vararg values: CSSNumberish): CSSNumericValue
+    override fun mul(vararg values: CSSNumberish): CSSNumericValue
+    override fun div(vararg values: CSSNumberish): CSSNumericValue
+    override fun min(vararg values: CSSNumberish): CSSNumericValue
+    override fun max(vararg values: CSSNumberish): CSSNumericValue
+
+    override fun equals(vararg values: CSSNumberish): Boolean
+
+    override fun to(unit: String): CSSUnitValue
+    override fun toSum(vararg units: String): CSSMathSum
+    override fun type(): CSSNumericType
+
+    companion object {
+        fun parse(cssText: String): CSSNumericValue
+    }
+}
+
+external interface CSSUnitValue : CSSNumericValue {
+    val value: Number
+    val unit: String
+}
+
+external interface CSSTypedUnitValue<T> : CSSNumericValue {
+    val value: Number
+    val unit: T
+}
+
+@JsName("CSSUnitValue")
+external class CSSUnitValueJS(value: Number, unit: String) : CSSNumericValueJS, CSSUnitValue {
+    override val value: Number
+    override val unit: String
+}
+
+// declare enum CSSMathOperator {
+//     'sum',
+//     'product',
+//     'negate',
+//     'invert',
+//     'min',
+//     'max',
+//     'clamp',
+// }
+enum class CSSMathOperator(val value: String) {
+    sum("sum"),
+    product("product"),
+    negate("negate"),
+    invert("invert"),
+    min("min"),
+    max("max"),
+    clamp("clamp")
+}
+
+open external class CSSMathValue : CSSNumericValueJS {
+    // readonly operator: CSSMathOperator
+}
+
+val CSSMathValue.operator
+    get() = CSSMathOperator.valueOf(this.asDynamic().operator)
+//    set(value) { this.asDynamic().operator = value.value }
+
+external class CSSMathSum(vararg args: CSSNumberish) : CSSMathValue {
+    val values: CSSNumericArray
+}
+
+external class CSSMathProduct(vararg args: CSSNumberish) : CSSMathValue {
+    val values: CSSNumericArray
+}
+
+external class CSSMathNegate(arg: CSSNumberish) : CSSMathValue {
+    val value: CSSNumericValue
+}
+
+external class CSSMathInvert(arg: CSSNumberish) : CSSMathValue {
+    val value: CSSNumericValue
+}
+
+external class CSSMathMin(vararg args: CSSNumberish) : CSSMathValue {
+    val values: CSSNumericArray
+}
+
+external class CSSMathMax(vararg args: CSSNumberish) : CSSMathValue {
+    val values: CSSNumericArray
+}
+
+// TODO(yavanosta) : conflict with base class properties
+// Since there is no support for this class in any browser, it's better
+// wait for the implementation.
+// declare class CSSMathClamp extends CSSMathValue {
+// constructor(min: CSSNumberish, val: CSSNumberish, max: CSSNumberish)
+//     readonly min: CSSNumericValue
+//     readonly val: CSSNumericValue
+//     readonly max: CSSNumericValue
+// }
+
+external class CSSNumericArray {
+    // TODO: [Symbol.iterator]() : IterableIterator<CSSNumericValue>
+    fun forEach(handler: (CSSNumericValue) -> Unit)
+    val length: Int
+
+    // readonly [index: number]: CSSNumericValue
+    operator fun get(index: Int): CSSNumericValue
+}
+
+external class CSSTransformValue(transforms: Array<CSSTransformComponent>) : CSSStyleValue {
+    // [Symbol.iterator]() : IterableIterator<CSSTransformComponent>
+    fun forEach(handler: (CSSTransformComponent) -> Unit)
+    val length: Int
+
+    // [index: number]: CSSTransformComponent
+    operator fun get(index: Int): CSSTransformComponent
+    operator fun set(index: Int, value: CSSTransformComponent)
+    val is2D: Boolean
+    fun toMatrix(): DOMMatrix
+}
+
+open external class CSSTransformComponent {
+    val is2D: Boolean
+    fun toMatrix(): DOMMatrix
+    // toString() : string
+}
+
+external class CSSTranslate(
+    x: CSSNumericValue,
+    y: CSSNumericValue,
+    z: CSSNumericValue? = definedExternally
+) : CSSTransformComponent {
+    val x: CSSNumericValue
+    val y: CSSNumericValue
+    val z: CSSNumericValue
+}
+
+external class CSSRotate(angle: CSSNumericValue) : CSSTransformComponent {
+    constructor(x: CSSNumberish, y: CSSNumberish, z: CSSNumberish, angle: CSSNumericValue)
+
+    val x: CSSNumberish
+    val y: CSSNumberish
+    val z: CSSNumberish
+    val angle: CSSNumericValue
+}
+
+external class CSSScale(
+    x: CSSNumberish,
+    y: CSSNumberish,
+    z: CSSNumberish? = definedExternally
+) : CSSTransformComponent {
+    val x: CSSNumberish
+    val y: CSSNumberish
+    val z: CSSNumberish
+}
+
+external class CSSSkew(ax: CSSNumericValue, ay: CSSNumericValue) : CSSTransformComponent {
+    val ax: CSSNumericValue
+    val ay: CSSNumericValue
+}
+
+external class CSSSkewX(ax: CSSNumericValue) : CSSTransformComponent {
+    val ax: CSSNumericValue
+}
+
+external class CSSSkewY(ay: CSSNumericValue) : CSSTransformComponent {
+    val ay: CSSNumericValue
+}
+
+/* Note that skew(x,y) is *not* the same as skewX(x) skewY(y),
+     thus the separate interfaces for all three. */
+
+external class CSSPerspective(length: CSSNumericValue) : CSSTransformComponent {
+    val length: CSSNumericValue
+}
+
+external class CSSMatrixComponent(
+    matrix: DOMMatrixReadOnly,
+    options: CSSMatrixComponentOptions? = definedExternally
+) : CSSTransformComponent {
+    val matrix: DOMMatrix
+}
+
+external interface CSSMatrixComponentOptions {
+    val is2D: Boolean
+}
+
+external class CSSImageValue : CSSStyleValue
+
+open external class StylePropertyMapReadOnly {
+    // TODO: [Symbol.iterator]() : IterableIterator<[string, CSSStyleValue[]]>
+
+    fun get(property: String): CSSStyleValue? // CSSStyleValue | undefined
+    fun getAll(property: String): Array<CSSStyleValue>
+    fun has(property: String): Boolean
+    val size: Number
+}
+
+fun StylePropertyMapReadOnly.forEach(handler: (String, Array<CSSStyleValue>) -> Unit) {
+    this.asDynamic().forEach { entry: Array<dynamic> ->
+        handler(
+            entry[0].unsafeCast<String>(),
+            entry[1].unsafeCast<Array<CSSStyleValue>>()
+        )
+    }
+}
+
+// CSSStyleValue | string
+interface StylePropertyValue {
+    companion object {
+        operator fun invoke(value: String) = value.unsafeCast<StylePropertyValue>()
+        operator fun invoke(value: Number) = value.unsafeCast<StylePropertyValue>()
+        operator fun invoke(value: CSSStyleValue) = value.unsafeCast<StylePropertyValue>()
+    }
+}
+
+fun StylePropertyValue.asString() = this.asDynamic() as? String
+fun StylePropertyValue.asNumber() = this.asDynamic() as? Number
+fun StylePropertyValue.asCSSStyleValue(): CSSStyleValue? = this.asDynamic() as? CSSStyleValueJS
+
+external class StylePropertyMap : StylePropertyMapReadOnly {
+    fun set(property: String, vararg values: StylePropertyValue)
+    fun append(property: String, vararg values: StylePropertyValue)
+    fun delete(property: String)
+    fun clear()
+}
+
+inline fun Element.computedStyleMap(): StylePropertyMapReadOnly =
+    this.asDynamic().computedStyleMap().unsafeCast<StylePropertyMapReadOnly>()
+
+external class CSS {
+    companion object {
+        fun number(value: Number): CSSUnitValue
+        fun percent(value: Number): CSSUnitValue
+
+        // <length>
+        fun em(value: Number): CSSUnitValue
+        fun ex(value: Number): CSSUnitValue
+        fun ch(value: Number): CSSUnitValue
+        fun ic(value: Number): CSSUnitValue
+        fun rem(value: Number): CSSUnitValue
+        fun lh(value: Number): CSSUnitValue
+        fun rlh(value: Number): CSSUnitValue
+        fun vw(value: Number): CSSUnitValue
+        fun vh(value: Number): CSSUnitValue
+        fun vi(value: Number): CSSUnitValue
+        fun vb(value: Number): CSSUnitValue
+        fun vmin(value: Number): CSSUnitValue
+        fun vmax(value: Number): CSSUnitValue
+        fun cm(value: Number): CSSUnitValue
+        fun mm(value: Number): CSSUnitValue
+        fun Q(value: Number): CSSUnitValue
+
+        //        function _in(value: Number) : CSSUnitValue
+//        export
+//        { _in as in }
+        fun pt(value: Number): CSSUnitValue
+        fun pc(value: Number): CSSUnitValue
+        fun px(value: Number): CSSUnitValue
+
+        // <angle>
+        fun deg(value: Number): CSSUnitValue
+        fun grad(value: Number): CSSUnitValue
+        fun rad(value: Number): CSSUnitValue
+        fun turn(value: Number): CSSUnitValue
+
+        // <time>
+        fun s(value: Number): CSSUnitValue
+        fun ms(value: Number): CSSUnitValue
+
+        // <frequency>
+        fun Hz(value: Number): CSSUnitValue
+        fun kHz(value: Number): CSSUnitValue
+
+        // <resolution>
+        fun dpi(value: Number): CSSUnitValue
+        fun dpcm(value: Number): CSSUnitValue
+        fun dppx(value: Number): CSSUnitValue
+
+        // <flex>
+        fun fr(value: Number): CSSUnitValue
+    }
+}
+
+@Suppress("unused")
+val cssTypedOMPolyfill = CSSTypedOMPolyfill.default(window)

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSBuilder.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+import androidx.compose.web.css.selectors.CSSSelector
+
+interface CSSBuilder : CSSStyleRuleBuilder, GenericStyleSheetBuilder<CSSBuilder> {
+    val root: CSSSelector
+    val self: CSSSelector
+}
+
+class CSSBuilderImpl(
+    override val root: CSSSelector,
+    override val self: CSSSelector,
+    rulesHolder: CSSRulesHolder
+) : CSSRuleBuilderImpl(), CSSBuilder, CSSRulesHolder by rulesHolder {
+    override fun style(selector: CSSSelector, cssRule: CSSBuilder.() -> Unit) {
+        val (style, rules) = buildCSS(root, selector, cssRule)
+        rules.forEach { add(it) }
+        add(selector, style)
+    }
+
+    override fun buildRules(rulesBuild: GenericStyleSheetBuilder<CSSBuilder>.() -> Unit) =
+        CSSBuilderImpl(root, self, StyleSheetBuilderImpl()).apply(rulesBuild).cssRules
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSHelpers.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@file:Suppress("UNUSED")
+
+package androidx.compose.web.css
+
+interface CSSAutoValue : CSSKeywordValue
+
+val auto = CSSKeywordValueJS("auto").unsafeCast<CSSAutoValue>()
+fun asCSSAutoValue(value: dynamic) = (value as? CSSKeywordValueJS).unsafeCast<CSSAutoValue>()
+
+// type CSSSizeOrAutoValue = CSSSizeValue | CSSAutoValue
+interface CSSSizeOrAutoValue : CSSStyleValue, StylePropertyValue {
+    companion object {
+        operator fun invoke(value: CSSSizeValue) = value.unsafeCast<CSSSizeOrAutoValue>()
+        operator fun invoke(value: CSSAutoValue) = value.unsafeCast<CSSSizeOrAutoValue>()
+    }
+}
+
+fun CSSSizeOrAutoValue.asCSSSizeValue() = this.asDynamic() as? CSSUnitValueJS
+fun CSSSizeOrAutoValue.asCSSAutoValue(): CSSAutoValue = asCSSAutoValue(this.asDynamic())
+
+enum class Direction {
+    rtl,
+    ltr;
+
+    override fun toString(): String = this.name
+}
+
+typealias LanguageCode = String

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSMediaRule.kt

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+interface CSSMediaQuery {
+    interface Invertible : CSSMediaQuery
+    interface Combinable : CSSMediaQuery
+    interface Atomic : Invertible, Combinable
+    data class Raw(val string: String) : Atomic {
+        override fun toString() = string
+    }
+    data class MediaType(val type: Enum) : Atomic {
+        enum class Enum {
+            all, print, screen, speech
+        }
+
+        override fun toString() = type.name
+    }
+
+    data class MediaFeature(
+        val name: String,
+        val value: StylePropertyValue? = null
+    ) : CSSMediaQuery, Atomic {
+        override fun equals(other: Any?): Boolean {
+            return if (other is MediaFeature) {
+                name == other.name && value.toString() == other.value.toString()
+            } else false
+        }
+
+        override fun toString() = "($name${ value?.let { ": $value)" } ?: "" }"
+    }
+
+    // looks like it doesn't work at least in chrome
+    data class NotFeature(val query: MediaFeature) : CSSMediaQuery {
+        override fun toString() = "(not $query)"
+    }
+
+    data class And(val mediaList: MutableList<Atomic>) : CSSMediaQuery, Invertible, Combinable {
+        override fun toString() = mediaList.joinToString(" and ")
+    }
+
+    data class Not(val query: Invertible) : CSSMediaQuery {
+        override fun toString() = "not $query"
+    }
+
+    data class Combine(val mediaList: MutableList<CSSMediaQuery>) : CSSMediaQuery {
+        override fun toString() = mediaList.joinToString(", ")
+    }
+
+    data class Only(val type: MediaType, val query: Combinable) : CSSMediaQuery, Invertible {
+        override fun toString() = "only $type and $query"
+    }
+
+    // looks like it doesn't work at least in chrome, maybe need fallback to Combine
+    data class Or(val mediaList: List<CSSMediaQuery>) {
+        override fun toString() = mediaList.joinToString(" or ")
+    }
+}
+
+class CSSMediaRuleDeclaration(
+    val query: CSSMediaQuery,
+    rules: CSSRuleDeclarationList
+) : CSSGroupingRuleDeclaration(rules) {
+    override val header: String
+        get() = "@media $query"
+
+    override fun equals(other: Any?): Boolean {
+        return if (other is CSSMediaRuleDeclaration) {
+            rules == other.rules && query == other.query
+        } else false
+    }
+}
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.media(
+    query: CSSMediaQuery,
+    rulesBuild: GenericStyleSheetBuilder<TBuilder>.() -> Unit
+) {
+    val rules = buildRules(rulesBuild)
+    add(CSSMediaRuleDeclaration(query, rules))
+}
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.media(
+    query: String,
+    rulesBuild: GenericStyleSheetBuilder<TBuilder>.() -> Unit
+) {
+    media(CSSMediaQuery.Raw(query), rulesBuild)
+}
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.media(
+    name: String,
+    value: StylePropertyValue? = null,
+    noinline rulesBuild: GenericStyleSheetBuilder<TBuilder>.() -> Unit
+) {
+    media(feature(name, value), rulesBuild)
+}
+
+fun feature(
+    name: String,
+    value: StylePropertyValue? = null
+) = CSSMediaQuery.MediaFeature(name, value)
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.media(
+    vararg mediaList: CSSMediaQuery,
+    noinline rulesBuild: GenericStyleSheetBuilder<TBuilder>.() -> Unit
+) {
+    media(combine(*mediaList), rulesBuild)
+}
+
+fun combine(
+    vararg mediaList: CSSMediaQuery
+) = CSSMediaQuery.Combine(mediaList.toMutableList())
+
+infix fun CSSMediaQuery.Atomic.and(
+    query: CSSMediaQuery.Atomic
+) = CSSMediaQuery.And(mutableListOf(this, query))
+
+infix fun CSSMediaQuery.And.and(
+    query: CSSMediaQuery.Atomic
+) = this.apply {
+    this.mediaList.add(query)
+}
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.not(
+    query: CSSMediaQuery.Invertible
+) = CSSMediaQuery.Not(query)
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.minWidth(value: CSSSizeValue) =
+    CSSMediaQuery.MediaFeature("min-width", StylePropertyValue(value))
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.maxWidth(value: CSSSizeValue) =
+    CSSMediaQuery.MediaFeature("max-width", StylePropertyValue(value))
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.minHeight(value: CSSSizeValue) =
+    CSSMediaQuery.MediaFeature("min-height", StylePropertyValue(value))
+
+fun <TBuilder> GenericStyleSheetBuilder<TBuilder>.maxHeight(value: CSSSizeValue) =
+    CSSMediaQuery.MediaFeature("max-height", StylePropertyValue(value))

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSPolyfill.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package androidx.compose.web.css
+
+import org.w3c.dom.Window
+
+@JsModule("css-typed-om")
+@JsNonModule
+abstract external class CSSTypedOMPolyfill {
+    companion object {
+        fun default(window: Window)
+    }
+}
+
+fun StylePropertyMap.clear() {
+    throw AssertionError("StylePropertyMap::clear isn't polyfilled")
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSProperties.kt

@@ -0,0 +1,427 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+fun StyleBuilder.opacity(value: Number) {
+    property("opacity", value(value))
+}
+
+fun StyleBuilder.order(value: Int) {
+    property("order", StylePropertyValue(value))
+}
+
+fun StyleBuilder.flexGrow(value: Number) {
+    property("flex-grow", StylePropertyValue(value))
+}
+
+fun StyleBuilder.flexShrink(value: Number) {
+    property("flex-shrink", StylePropertyValue(value))
+}
+
+fun StyleBuilder.opacity(value: CSSpercentValue) {
+    property("opacity", value(value.value as Double / 100))
+}
+
+fun StyleBuilder.color(value: String) {
+    property("color", value(value))
+}
+
+fun StyleBuilder.color(value: Color) {
+    // color hasn't Typed OM yet
+    property("color", value.styleValue())
+}
+
+fun StyleBuilder.backgroundColor(value: CSSVariableValue<Color>) {
+    property("background-color", value)
+}
+
+fun StyleBuilder.backgroundColor(value: Color) {
+    property("background-color", value.styleValue())
+}
+
+fun StyleBuilder.backgroundColor(value: String) {
+    property("background-color", value(value))
+}
+
+enum class LineStyle {
+    None,
+    Hidden,
+    Dotted,
+    Dashed,
+    Solid,
+    Double,
+    Groove,
+    Ridge,
+    Inset,
+    Outset
+}
+
+enum class DisplayStyle(val value: String) {
+    Block("block"),
+    Inline("inline"),
+    InlineBlock("inline-block"),
+    Flex("flex"),
+    LegacyInlineFlex("inline-flex"),
+    Grid("grid"),
+    LegacyInlineGrid("inline-grid"),
+    FlowRoot("flow-root"),
+
+    None("none"),
+    Contents("contents"),
+
+// TODO(shabunc): This properties behave them iconsistenly in both Chrome and Firefox so I turned the off so far
+//    BlockFlow("block flow"),
+//    InlineFlow("inline flow"),
+//    InlineFlowRoot("inline flow-root"),
+//    BlocklFlex("block flex"),
+//    InlineFlex("inline flex"),
+//    BlockGrid("block grid"),
+//    InlineGrid("inline grid"),
+//    BlockFlowRoot("block flow-root"),
+
+    Table("table"),
+    TableRow("table-row"),
+    ListItem("list-item"),
+
+    Inherit("inherit"),
+    Initial("initial"),
+    Unset("unset")
+}
+
+enum class FlexDirection(val value: String) {
+    Row("row"),
+    RowReverse("row-reverse"),
+    Column("column"),
+    ColumnReverse("column-reverse")
+}
+
+enum class FlexWrap(val value: String) {
+    Wrap("wrap"),
+    Nowrap("nowrap"),
+    WrapReverse("wrap-reverse")
+}
+
+enum class JustifyContent(val value: String) {
+    Center("center"),
+    Start("start"),
+    End("end"),
+    FlexStart("flex-start"),
+    FlexEnd("flex-end"),
+    Left("left"),
+    Right("right"),
+    Normal("normal"),
+    SpaceBetween("space-between"),
+    SpaceAround("space-around"),
+    SpaceEvenly("space-evenly"),
+    Stretch("stretch"),
+    Inherit("inherit"),
+    Initial("initial"),
+    Unset("unset"),
+    SafeCenter("safe center"),
+    UnsafeCenter("unsafe center"),
+}
+
+enum class AlignSelf(val value: String) {
+    Auto("auto"),
+    Normal("normal"),
+    Center("center"),
+    Start("start"),
+    End("end"),
+    SelfStart("self-start"),
+    SelfEnd("self-end"),
+    FlexStart("flex-start"),
+    FlexEnd("flex-end"),
+    Baseline("baseline"),
+//    FirstBaseline("first baseline"),
+//    LastBaseline("last baseline"),
+    Stretch("stretch"),
+    SafeCenter("safe center"),
+    UnsafeCenter("unsafe center"),
+    Inherit("inherit"),
+    Initial("initial"),
+    Unset("unset")
+}
+
+enum class AlignItems(val value: String) {
+    Normal("normal"),
+    Stretch("stretch"),
+    Center("center"),
+    Start("start"),
+    End("end"),
+    FlexStart("flex-start"),
+    FlexEnd("flex-end"),
+    Baseline("baseline"),
+//    FirstBaseline("first baseline"),
+//    LastBaseline("last baseline"),
+    SafeCenter("safe center"),
+    UnsafeCenter("unsafe center"),
+
+    Inherit("inherit"),
+    Initial("initial"),
+    Unset("unset")
+}
+
+enum class AlignContent(val value: String) {
+    Center("center"),
+    Start("start"),
+    End("end"),
+    FlexStart("flex-start"),
+    FlexEnd("flex-end"),
+    Baseline("baseline"),
+//    FirstBaseline("first baseline"),
+//    LastBaseline("last baseline"),
+    SafeCenter("safe center"),
+    UnsafeCenter("unsafe center"),
+    SpaceBetween("space-between"),
+    SpaceAround("space-around"),
+    SpaceEvenly("space-evenly"),
+    Stretch("stretch"),
+
+    Inherit("inherit"),
+    Initial("initial"),
+    Unset("unset")
+}
+
+enum class Position(val value: String) {
+    Static("static"),
+    Relative("relative"),
+    Absolute("absolute"),
+    Sticky("sticky"),
+    Fixed("fixed")
+}
+
+class CSSBorder : CustomStyleValue {
+    var width: StylePropertyValue? = null
+    var style: StylePropertyValue? = null
+    var color: StylePropertyValue? = null
+
+    fun width(size: CSSSizeValue) {
+        width = StylePropertyValue(size)
+    }
+
+    fun style(style: LineStyle) {
+        this.style = StylePropertyValue(style.name)
+    }
+
+    fun color(color: Color) {
+        this.color = color.styleValue()
+    }
+
+    fun color(color: CSSVariableValue<Color>) {
+        this.color = color
+    }
+
+    override fun equals(other: Any?): Boolean {
+        return if (other is CSSBorder) {
+            styleValue().toString() == other.styleValue().toString()
+        } else false
+    }
+
+    override fun styleValue(): StylePropertyValue {
+        val values = listOfNotNull(width, style, color)
+        return StylePropertyValue(values.joinToString(" "))
+    }
+}
+
+inline fun StyleBuilder.border(crossinline borderBuild: CSSBorder.() -> Unit) {
+    val border = CSSBorder().apply(borderBuild)
+    property("border", border.styleValue())
+}
+
+fun StyleBuilder.border(
+    width: CSSSizeValue? = null,
+    style: LineStyle? = null,
+    color: Color? = null
+) {
+    border {
+        width?.let { width(it) }
+        style?.let { style(it) }
+        color?.let { color(it) }
+    }
+}
+
+fun StyleBuilder.display(displayStyle: DisplayStyle) {
+    property("display", StylePropertyValue(displayStyle.value))
+}
+
+fun StyleBuilder.flexDirection(flexDirection: FlexDirection) {
+    property("flex-direction", StylePropertyValue(flexDirection.value))
+}
+
+fun StyleBuilder.flexWrap(flexWrap: FlexWrap) {
+    property("flex-wrap", StylePropertyValue(flexWrap.value))
+}
+
+fun StyleBuilder.flexFlow(flexDirection: FlexDirection, flexWrap: FlexWrap) {
+    property(
+        "flex-flow",
+        StylePropertyValue("${flexDirection.value} ${flexWrap.value}")
+    )
+}
+
+fun StyleBuilder.justifyContent(justifyContent: JustifyContent) {
+    property(
+        "justify-content",
+        StylePropertyValue(justifyContent.value)
+    )
+}
+fun StyleBuilder.alignSelf(alignSelf: AlignSelf) {
+    property(
+        "align-self",
+        StylePropertyValue(alignSelf.value)
+    )
+}
+
+fun StyleBuilder.alignItems(alignItems: AlignItems) {
+    property(
+        "align-items",
+        StylePropertyValue(alignItems.value)
+    )
+}
+
+fun StyleBuilder.alignContent(alignContent: AlignContent) {
+    property(
+        "align-content",
+        StylePropertyValue(alignContent.value)
+    )
+}
+
+fun StyleBuilder.position(position: Position) {
+    property(
+        "position",
+        StylePropertyValue(position.value)
+    )
+}
+
+fun StyleBuilder.width(value: CSSSizeOrAutoValue) {
+    property("width", value)
+}
+
+fun StyleBuilder.borderRadius(r: CSSSizeValue) {
+    property("border-radius", StylePropertyValue(r.toString()))
+}
+
+fun StyleBuilder.borderRadius(topLeft: CSSSizeValue, bottomRight: CSSSizeValue) {
+    property("border-radius", StylePropertyValue("$topLeft $bottomRight"))
+}
+
+fun StyleBuilder.borderRadius(
+    topLeft: CSSSizeValue,
+    topRightAndBottomLeft: CSSSizeValue,
+    bottomRight: CSSSizeValue
+) {
+    property("border-radius", StylePropertyValue("$topLeft $topRightAndBottomLeft $bottomRight"))
+}
+
+fun StyleBuilder.borderRadius(
+    topLeft: CSSSizeValue,
+    topRight: CSSSizeValue,
+    bottomRight: CSSSizeValue,
+    bottomLeft: CSSSizeValue
+) {
+    property("border-radius", StylePropertyValue("$topLeft $topRight $bottomRight $bottomLeft"))
+}
+
+fun StyleBuilder.width(value: CSSSizeValue) {
+    width(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.width(value: CSSAutoValue) {
+    width(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.height(value: CSSSizeOrAutoValue) {
+    property("height", value)
+}
+
+fun StyleBuilder.height(value: CSSSizeValue) {
+    height(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.height(value: CSSAutoValue) {
+    height(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.top(value: CSSSizeOrAutoValue) {
+    property("top", value)
+}
+
+fun StyleBuilder.top(value: CSSSizeValue) {
+    top(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.top(value: CSSAutoValue) {
+    top(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.bottom(value: CSSSizeOrAutoValue) {
+    property("bottom", value)
+}
+
+fun StyleBuilder.bottom(value: CSSSizeValue) {
+    bottom(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.bottom(value: CSSAutoValue) {
+    bottom(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.left(value: CSSSizeOrAutoValue) {
+    property("left", value)
+}
+
+fun StyleBuilder.left(value: CSSSizeValue) {
+    left(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.left(value: CSSAutoValue) {
+    left(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.right(value: CSSSizeOrAutoValue) {
+    property("right", value)
+}
+
+fun StyleBuilder.right(value: CSSSizeValue) {
+    right(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.right(value: CSSAutoValue) {
+    right(CSSSizeOrAutoValue(value))
+}
+
+fun StyleBuilder.fontSize(value: CSSSizeValue) {
+    property("font-size", value(value))
+}
+
+fun StyleBuilder.margin(value: CSSSizeValue) {
+    // marign hasn't Typed OM yet
+    property("margin", value(value.toString()))
+}
+
+fun StyleBuilder.marginLeft(value: CSSSizeValue) {
+    property("margin-left", value(value.toString()))
+}
+
+fun StyleBuilder.marginTop(value: CSSSizeValue) {
+    property("margin-top", value(value.toString()))
+}
+
+fun StyleBuilder.padding(value: CSSSizeValue) {
+    // padding hasn't Typed OM yet
+    property("padding", value(value.toString()))
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSRules.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+import androidx.compose.web.css.selectors.CSSSelector
+
+interface CSSStyleRuleBuilder : StyleBuilder
+
+open class CSSRuleBuilderImpl : CSSStyleRuleBuilder, StyleBuilderImpl()
+
+abstract class CSSRuleDeclaration {
+    abstract val header: String
+
+    abstract override fun equals(other: Any?): Boolean
+}
+
+data class CSSStyleRuleDeclaration(
+    val selector: CSSSelector,
+    val style: StyleHolder
+) : CSSRuleDeclaration() {
+    override val header
+        get() = selector.toString()
+}
+
+abstract class CSSGroupingRuleDeclaration(
+    val rules: CSSRuleDeclarationList
+) : CSSRuleDeclaration()
+
+typealias CSSRuleDeclarationList = List<CSSRuleDeclaration>
+typealias MutableCSSRuleDeclarationList = MutableList<CSSRuleDeclaration>
+
+fun buildCSSStyleRule(cssRule: CSSStyleRuleBuilder.() -> Unit): StyleHolder {
+    val builder = CSSRuleBuilderImpl()
+    builder.cssRule()
+    return builder
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSUnits.kt

@@ -0,0 +1,142 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@file:Suppress("UNUSED")
+
+package androidx.compose.web.css
+
+external interface CSSSizeValue : CSSUnitValue
+
+// fake interfaces to distinguish units
+external interface CSSRelValue : CSSSizeValue
+external interface CSSpercentValue : CSSRelValue
+external interface CSSemValue : CSSRelValue
+external interface CSSexValue : CSSRelValue
+external interface CSSchValue : CSSRelValue
+external interface CSSicValue : CSSRelValue
+external interface CSSremValue : CSSRelValue
+external interface CSSlhValue : CSSRelValue
+external interface CSSrlhValue : CSSRelValue
+external interface CSSvwValue : CSSRelValue
+external interface CSSvhValue : CSSRelValue
+external interface CSSviValue : CSSRelValue
+external interface CSSvbValue : CSSRelValue
+external interface CSSvminValue : CSSRelValue
+external interface CSSvmaxValue : CSSRelValue
+external interface CSScmValue : CSSRelValue
+external interface CSSmmValue : CSSRelValue
+external interface CSSQValue : CSSRelValue
+
+external interface CSSAbsValue : CSSSizeValue
+external interface CSSptValue : CSSAbsValue
+external interface CSSpcValue : CSSAbsValue
+external interface CSSpxValue : CSSAbsValue
+
+external interface CSSangleValue : CSSUnitValue
+external interface CSSdegValue : CSSangleValue
+external interface CSSgradValue : CSSangleValue
+external interface CSSradValue : CSSangleValue
+external interface CSSturnValue : CSSangleValue
+
+external interface CSSTimeValue : CSSUnitValue
+external interface CSSsValue : CSSTimeValue
+external interface CSSmsValue : CSSTimeValue
+
+external interface CSSFrequencyValue : CSSUnitValue
+external interface CSSHzValue : CSSFrequencyValue
+external interface CSSkHzValue : CSSFrequencyValue
+
+external interface CSSResolutionValue : CSSUnitValue
+external interface CSSdpiValue : CSSResolutionValue
+external interface CSSdpcmValue : CSSResolutionValue
+external interface CSSdppxValue : CSSResolutionValue
+
+external interface CSSFlexValue : CSSUnitValue
+external interface CSSfrValue : CSSFlexValue
+
+val Number.number
+    get(): CSSUnitValue = CSS.number(this)
+
+val Number.percent
+    get(): CSSpercentValue = CSS.percent(this).unsafeCast<CSSpercentValue>()
+
+val Number.em
+    get(): CSSemValue = CSS.em(this).unsafeCast<CSSemValue>()
+val Number.ex
+    get(): CSSexValue = CSS.ex(this).unsafeCast<CSSexValue>()
+val Number.ch
+    get(): CSSchValue = CSS.ch(this).unsafeCast<CSSchValue>()
+val Number.ic
+    get(): CSSicValue = CSS.ic(this).unsafeCast<CSSicValue>()
+val Number.rem
+    get(): CSSremValue = CSS.rem(this).unsafeCast<CSSremValue>()
+val Number.lh
+    get(): CSSlhValue = CSS.lh(this).unsafeCast<CSSlhValue>()
+val Number.rlh
+    get(): CSSrlhValue = CSS.rlh(this).unsafeCast<CSSrlhValue>()
+val Number.vw
+    get(): CSSvwValue = CSS.vw(this).unsafeCast<CSSvwValue>()
+val Number.vh
+    get(): CSSvhValue = CSS.vh(this).unsafeCast<CSSvhValue>()
+val Number.vi
+    get(): CSSviValue = CSS.vi(this).unsafeCast<CSSviValue>()
+val Number.vb
+    get(): CSSvbValue = CSS.vb(this).unsafeCast<CSSvbValue>()
+val Number.vmin
+    get(): CSSvminValue = CSS.vmin(this).unsafeCast<CSSvminValue>()
+val Number.vmax
+    get(): CSSvmaxValue = CSS.vmax(this).unsafeCast<CSSvmaxValue>()
+val Number.cm
+    get(): CSScmValue = CSS.cm(this).unsafeCast<CSScmValue>()
+val Number.mm
+    get(): CSSmmValue = CSS.mm(this).unsafeCast<CSSmmValue>()
+val Number.Q
+    get(): CSSQValue = CSS.Q(this).unsafeCast<CSSQValue>()
+
+val Number.pt
+    get(): CSSptValue = CSS.pt(this).unsafeCast<CSSptValue>()
+val Number.pc
+    get(): CSSpcValue = CSS.pc(this).unsafeCast<CSSpcValue>()
+val Number.px
+    get(): CSSpxValue = CSS.px(this).unsafeCast<CSSpxValue>()
+
+val Number.deg
+    get(): CSSdegValue = CSS.deg(this).unsafeCast<CSSdegValue>()
+val Number.grad
+    get(): CSSgradValue = CSS.grad(this).unsafeCast<CSSgradValue>()
+val Number.rad
+    get(): CSSradValue = CSS.rad(this).unsafeCast<CSSradValue>()
+val Number.turn
+    get(): CSSturnValue = CSS.turn(this).unsafeCast<CSSturnValue>()
+
+val Number.s
+    get(): CSSsValue = CSS.s(this).unsafeCast<CSSsValue>()
+val Number.ms
+    get(): CSSmsValue = CSS.ms(this).unsafeCast<CSSmsValue>()
+
+val Number.Hz
+    get(): CSSHzValue = CSS.Hz(this).unsafeCast<CSSHzValue>()
+val Number.kHz
+    get(): CSSkHzValue = CSS.kHz(this).unsafeCast<CSSkHzValue>()
+
+val Number.dpi
+    get(): CSSdpiValue = CSS.dpi(this).unsafeCast<CSSdpiValue>()
+val Number.dpcm
+    get(): CSSdpcmValue = CSS.dpcm(this).unsafeCast<CSSdpcmValue>()
+val Number.dppx
+    get(): CSSdppxValue = CSS.dppx(this).unsafeCast<CSSdppxValue>()
+
+val Number.fr
+    get(): CSSfrValue = CSS.fr(this).unsafeCast<CSSfrValue>()

web/core/src/jsMain/kotlin/androidx/compose/web/css/Color.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+abstract class Color : CustomStyleValue {
+    override fun styleValue(): StylePropertyValue = StylePropertyValue(toString())
+
+    data class Named(val value: String) : Color() {
+        override fun toString(): String = value
+    }
+
+    data class RGB(val r: Number, val g: Number, val b: Number) : Color() {
+        override fun toString(): String = "rgb($r, $g, $b)"
+    }
+
+    data class RGBA(val r: Number, val g: Number, val b: Number, val a: Number) : Color() {
+        override fun toString(): String = "rgba($r, $g, $b, $a)"
+    }
+
+    data class HSL(val h: CSSangleValue, val s: Number, val l: Number) : Color() {
+        constructor(h: Number, s: Number, l: Number) : this(h.deg, s, l)
+
+        override fun toString(): String = "hsl($h, $s%, $l%)"
+    }
+
+    data class HSLA(val h: CSSangleValue, val s: Number, val l: Number, val a: Number) : Color() {
+        constructor(h: Number, s: Number, l: Number, a: Number) : this(h.deg, s, l, a)
+
+        override fun toString(): String = "hsla($h, $s%, $l%, $a)"
+    }
+
+    companion object {
+        operator fun invoke(name: String) = Named(name)
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/StyleBuilder.kt

@@ -0,0 +1,136 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+import kotlin.properties.ReadOnlyProperty
+
+interface StyleBuilder {
+    fun property(propertyName: String, value: StylePropertyValue)
+    fun variable(variableName: String, value: StylePropertyValue)
+
+    operator fun <TValue> CSSStyleVariable<TValue>.invoke(value: TValue) {
+        variable(this.name, (value as? CustomStyleValue)?.styleValue() ?: value(value.toString()))
+    }
+}
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun StyleBuilder.value(value: String) = StylePropertyValue(value)
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun StyleBuilder.value(value: Number) = StylePropertyValue(value)
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun StyleBuilder.value(value: CSSStyleValue) = StylePropertyValue(value)
+
+fun variableValue(variableName: String, fallback: StylePropertyValue? = null) =
+    StylePropertyValue("var(--$variableName${fallback?.let { ", $it" } ?: ""})")
+
+interface CSSVariableValue<TValue> : StylePropertyValue {
+    companion object {
+        operator fun <TValue> invoke(value: String) =
+            StylePropertyValue(value).unsafeCast<CSSVariableValue<TValue>>()
+        operator fun <TValue> invoke(value: Number) =
+            StylePropertyValue(value).unsafeCast<CSSVariableValue<TValue>>()
+        operator fun <TValue : CSSStyleValue> invoke(value: TValue) =
+            StylePropertyValue(value).unsafeCast<CSSVariableValue<TValue>>()
+
+        operator fun <TValue> invoke(value: StylePropertyValue) =
+            value.unsafeCast<CSSVariableValue<TValue>>()
+    }
+}
+
+// after adding `variable` word `add` became ambiguous
+@Deprecated(
+    "use property instead, will remove it soon",
+    ReplaceWith("property(propertyName, value)")
+)
+fun StyleBuilder.add(
+    propertyName: String,
+    value: StylePropertyValue
+) = property(propertyName, value)
+
+interface CSSVariables
+
+interface CSSVariable {
+    val name: String
+}
+
+interface CustomStyleValue {
+    fun styleValue(): StylePropertyValue
+}
+
+data class CSSStyleVariable<TValue>(override val name: String) : CSSVariable
+
+fun <TValue> CSSStyleVariable<TValue>.value(fallback: TValue? = null) =
+    CSSVariableValue<TValue>(
+        variableValue(
+            name,
+            fallback?.let {
+                (fallback as? CustomStyleValue)?.styleValue()
+                    ?: StylePropertyValue(fallback.toString())
+            }
+        )
+    )
+
+fun <TValue> CSSVariables.variable() =
+    ReadOnlyProperty<Any?, CSSStyleVariable<TValue>> { _, property ->
+        CSSStyleVariable(property.name)
+    }
+
+interface StyleHolder {
+    val properties: StylePropertyList
+    val variables: StylePropertyList
+}
+
+open class StyleBuilderImpl : StyleBuilder, StyleHolder {
+    override val properties: MutableStylePropertyList = mutableListOf()
+    override val variables: MutableStylePropertyList = mutableListOf()
+
+    override fun property(propertyName: String, value: StylePropertyValue) {
+        properties.add(StylePropertyDeclaration(propertyName, value))
+    }
+
+    override fun variable(variableName: String, value: StylePropertyValue) {
+        variables.add(StylePropertyDeclaration(variableName, value))
+    }
+
+    // StylePropertyValue is js native object without equals
+    override fun equals(other: Any?): Boolean {
+        return if (other is StyleHolder) {
+            properties.nativeEquals(other.properties) &&
+                variables.nativeEquals(other.variables)
+        } else false
+    }
+}
+
+data class StylePropertyDeclaration(
+    val name: String,
+    val value: StylePropertyValue
+)
+typealias StylePropertyList = List<StylePropertyDeclaration>
+typealias MutableStylePropertyList = MutableList<StylePropertyDeclaration>
+
+fun StylePropertyList.nativeEquals(properties: StylePropertyList): Boolean {
+    if (this.size != properties.size) return false
+
+    var index = 0
+    return all { prop ->
+        val otherProp = properties[index++]
+        prop.name == otherProp.name &&
+            prop.value.toString() == otherProp.value.toString()
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/StyleSheet.kt

@@ -0,0 +1,133 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.setValue
+import androidx.compose.web.css.selectors.CSSSelector
+import androidx.compose.web.css.selectors.className
+import androidx.compose.web.elements.Style
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+class CSSRulesHolderState : CSSRulesHolder {
+    override var cssRules: CSSRuleDeclarationList by mutableStateOf(listOf())
+
+    override fun add(cssRule: CSSRuleDeclaration) {
+        cssRules += cssRule
+    }
+}
+
+/**
+ * Represents a collection of the css style rules.
+ * StyleSheet needs to be mounted.
+ * @see [Style]
+ *
+ * Example:
+ * ```
+ * object AppStylesheet : StyleSheet() {
+ *     val containerClass by style {
+ *         padding(24.px)
+ *     }
+ * }
+ * ```
+ *
+ * Usage Example:
+ * ```
+ *    Style(AppStylesheet) // this mounts the stylesheet
+ *    Div(classes = listOf(AppStylesheet.containerClass),...)
+ * ```
+ */
+open class StyleSheet(
+    private val rulesHolder: CSSRulesHolder = CSSRulesHolderState()
+) : StyleSheetBuilder, CSSRulesHolder by rulesHolder {
+    private val boundClasses = mutableMapOf<String, CSSRuleDeclarationList>()
+
+    protected fun style(cssRule: CSSBuilder.() -> Unit) = CSSHolder(cssRule)
+
+    companion object {
+        var counter = 0
+    }
+
+    data class CSSSelfSelector(var selector: CSSSelector? = null) : CSSSelector() {
+        override fun toString(): String = selector.toString()
+        override fun equals(other: Any?): Boolean {
+            return other is CSSSelfSelector
+        }
+    }
+
+    // TODO: just proof of concept, do not use it
+    fun css(cssBuild: CSSBuilder.() -> Unit): String {
+        val selfSelector = CSSSelfSelector()
+        val (style, newCssRules) = buildCSS(selfSelector, selfSelector, cssBuild)
+        val cssRule = cssRules.find {
+            it is CSSStyleRuleDeclaration &&
+                it.selector is CSSSelector.CSSClass && it.style == style &&
+                (boundClasses[it.selector.className] ?: emptyList()) == newCssRules
+        }.unsafeCast<CSSStyleRuleDeclaration?>()
+        return if (cssRule != null) {
+            cssRule.selector.unsafeCast<CSSSelector.CSSClass>().className
+        } else {
+            val classNameSelector = className("auto-${counter++}")
+            selfSelector.selector = classNameSelector
+            add(classNameSelector, style)
+            newCssRules.forEach { add(it) }
+            boundClasses[classNameSelector.className] = newCssRules
+            classNameSelector.className
+        }
+    }
+
+    protected class CSSHolder(val cssBuilder: CSSBuilder.() -> Unit) {
+        operator fun provideDelegate(
+            sheet: StyleSheet,
+            property: KProperty<*>
+        ): ReadOnlyProperty<Any?, String> {
+            val sheetName = "${sheet::class.simpleName}-"
+            val selector = className("$sheetName${property.name}")
+            val (properties, rules) = buildCSS(selector, selector, cssBuilder)
+            sheet.add(selector, properties)
+            rules.forEach { sheet.add(it) }
+
+            return ReadOnlyProperty { _, _ ->
+                selector.className
+            }
+        }
+    }
+
+    override fun buildRules(rulesBuild: GenericStyleSheetBuilder<CSSStyleRuleBuilder>.() -> Unit) =
+        StyleSheet().apply(rulesBuild).cssRules
+}
+
+fun buildCSS(
+    thisClass: CSSSelector,
+    thisContext: CSSSelector,
+    cssRule: CSSBuilder.() -> Unit
+): Pair<StyleHolder, CSSRuleDeclarationList> {
+    val styleSheet = StyleSheetBuilderImpl()
+    val builder = CSSBuilderImpl(thisClass, thisContext, styleSheet)
+    builder.cssRule()
+    return builder to styleSheet.cssRules
+}
+
+@Composable
+inline fun Style(
+    styleSheet: CSSRulesHolder
+) {
+    Style(cssRules = styleSheet.cssRules)
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/StyleSheetBuilder.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css
+
+import androidx.compose.web.css.selectors.CSSSelector
+
+interface CSSRulesHolder {
+    val cssRules: CSSRuleDeclarationList
+    fun add(cssRule: CSSRuleDeclaration)
+    fun add(selector: CSSSelector, style: StyleHolder) {
+        add(CSSStyleRuleDeclaration(selector, style))
+    }
+}
+
+interface GenericStyleSheetBuilder<TBuilder> : CSSRulesHolder {
+    fun buildRules(
+        rulesBuild: GenericStyleSheetBuilder<TBuilder>.() -> Unit
+    ): CSSRuleDeclarationList
+
+    fun style(selector: CSSSelector, cssRule: TBuilder.() -> Unit)
+
+    operator fun CSSSelector.invoke(cssRule: TBuilder.() -> Unit) {
+        style(this, cssRule)
+    }
+
+    infix fun CSSSelector.style(cssRule: TBuilder.() -> Unit) {
+        style(this, cssRule)
+    }
+
+    operator fun String.invoke(cssRule: TBuilder.() -> Unit) {
+        style(CSSSelector.Raw(this), cssRule)
+    }
+
+    infix fun String.style(cssRule: TBuilder.() -> Unit) {
+        style(CSSSelector.Raw(this), cssRule)
+    }
+}
+
+interface StyleSheetBuilder : CSSRulesHolder, GenericStyleSheetBuilder<CSSStyleRuleBuilder> {
+    override fun style(selector: CSSSelector, cssRule: CSSStyleRuleBuilder.() -> Unit) {
+        add(selector, buildCSSStyleRule(cssRule))
+    }
+}
+
+open class StyleSheetBuilderImpl : StyleSheetBuilder {
+    override val cssRules: MutableCSSRuleDeclarationList = mutableListOf()
+
+    override fun add(cssRule: CSSRuleDeclaration) {
+        cssRules.add(cssRule)
+    }
+
+    override fun buildRules(rulesBuild: GenericStyleSheetBuilder<CSSStyleRuleBuilder>.() -> Unit) =
+        StyleSheetBuilderImpl().apply(rulesBuild).cssRules
+}

web/core/src/jsMain/kotlin/androidx/compose/web/css/selectors/CSSSelectors.kt

@@ -0,0 +1,257 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.css.selectors
+
+import androidx.compose.web.css.LanguageCode
+
+sealed class Nth {
+    data class Functional(val a: Int? = null, val b: Int? = null) {
+        override fun toString(): String = when {
+            a != null && b != null -> "${a}n+$b"
+            a != null -> "${a}n"
+            b != null -> "$b"
+            else -> ""
+        }
+    }
+    object Odd : Nth() {
+        override fun toString(): String = "odd"
+    }
+    object Even : Nth() {
+        override fun toString(): String = "even"
+    }
+}
+
+open class CSSSelector {
+    override fun equals(other: Any?): Boolean {
+        return toString() == other.toString()
+    }
+
+    data class Raw(val selector: String) : CSSSelector() {
+        override fun toString(): String = selector
+    }
+
+    object Universal : CSSSelector() {
+        override fun toString(): String = "*"
+    }
+
+    data class Type(val type: String) : CSSSelector() {
+        override fun toString(): String = type
+    }
+
+    data class CSSClass(val className: String) : CSSSelector() {
+        override fun toString(): String = ".$className"
+    }
+
+    data class Id(val id: String) : CSSSelector() {
+        override fun toString(): String = "#$id"
+    }
+
+    data class Attribute(
+        val name: String,
+        val value: String? = null,
+        val operator: Operator = Operator.Equals,
+        val caseSensitive: Boolean = true
+    ) : CSSSelector() {
+        enum class Operator(val value: String) {
+            Equals("="),
+            ListContains("~="),
+            Hyphened("|="),
+            Prefixed("^="),
+            Suffixed("$="),
+            Contains("*=")
+        }
+        override fun toString(): String {
+            val valueStr = value?.let {
+                "${operator.value}$value${if (!caseSensitive) " i" else ""}"
+            } ?: ""
+            return "[$name$valueStr]"
+        }
+    }
+
+    data class Combine(val selectors: MutableList<CSSSelector>) : CSSSelector() {
+        override fun toString(): String = selectors.joinToString("")
+    }
+
+    data class Group(val selectors: List<CSSSelector>) : CSSSelector() {
+        override fun toString(): String = selectors.joinToString(", ")
+    }
+
+    data class Descendant(val parent: CSSSelector, val selected: CSSSelector) : CSSSelector() {
+        override fun toString(): String = "$parent $selected"
+    }
+
+    data class Child(val parent: CSSSelector, val selected: CSSSelector) : CSSSelector() {
+        override fun toString(): String = "$parent > $selected"
+    }
+
+    data class Sibling(val prev: CSSSelector, val selected: CSSSelector) : CSSSelector() {
+        override fun toString(): String = "$prev ~ $selected"
+    }
+
+    data class Adjacent(val prev: CSSSelector, val selected: CSSSelector) : CSSSelector() {
+        override fun toString(): String = "$prev + $selected"
+    }
+
+    open class PseudoClass(val name: String) : CSSSelector() {
+        override fun equals(other: Any?): Boolean {
+            return if (other is PseudoClass) {
+                name == other.name && argsStr() == other.argsStr()
+            } else false
+        }
+        open fun argsStr(): String? = null
+        override fun toString(): String = ":$name${argsStr()?.let { "($it)" } ?: ""}"
+
+        companion object {
+            // Location pseudo-classes
+            val anyLink = PseudoClass("any-link")
+            val link = PseudoClass("link")
+            val visited = PseudoClass("visited")
+            val localLink = PseudoClass("local-link")
+            val target = PseudoClass("target")
+            val targetWithin = PseudoClass("target-within")
+            val scope = PseudoClass("scope")
+
+            // User action pseudo-classes
+            val hover = PseudoClass("hover")
+            val active = PseudoClass("active")
+            val focus = PseudoClass("focus")
+            val focusVisible = PseudoClass("focus-visible")
+
+            // Resource state pseudo-classes
+            val playing = PseudoClass("playing")
+            val paused = PseudoClass("paused")
+
+            // The input pseudo-classes
+            val autofill = PseudoClass("autofill")
+            val enabled = PseudoClass("enabled")
+            val disabled = PseudoClass("disabled")
+            val readOnly = PseudoClass("read-only")
+            val readWrite = PseudoClass("read-write")
+            val placeholderShown = PseudoClass("placeholder-shown")
+            val default = PseudoClass("default")
+            val checked = PseudoClass("checked")
+            val indeterminate = PseudoClass("indeterminate")
+            val blank = PseudoClass("blank")
+            val valid = PseudoClass("valid")
+            val invalid = PseudoClass("invalid")
+            val inRange = PseudoClass("in-range")
+            val outOfRange = PseudoClass("out-of-range")
+            val required = PseudoClass("required")
+            val optional = PseudoClass("optional")
+            val userInvalid = PseudoClass("user-invalid")
+
+            // Tree-structural pseudo-classes
+            val root = PseudoClass("root")
+            val empty = PseudoClass("empty")
+            val first = PseudoClass("first")
+            val firstChild = PseudoClass("first-child")
+            val lastChild = PseudoClass("last-child")
+            val onlyChild = PseudoClass("only-child")
+            val firstOfType = PseudoClass("first-of-type")
+            val lastOfType = PseudoClass("last-of-type")
+            val onlyOfType = PseudoClass("only-of-type")
+            val host = PseudoClass("host")
+
+            // Etc
+            val defined = PseudoClass("defined")
+            val left = PseudoClass("left")
+            val right = PseudoClass("right")
+        }
+
+        // Linguistic pseudo-classes
+        class Lang(val langCode: LanguageCode) : PseudoClass("lang") {
+            override fun argsStr() = langCode
+        }
+
+        // Tree-structural pseudo-classes
+        class NthChild(val nth: Nth) : PseudoClass("nth-child") {
+            override fun argsStr() = "$nth"
+        }
+        class NthLastChild(val nth: Nth) : PseudoClass("nth-last-child") {
+            override fun argsStr() = "$nth"
+        }
+        class NthOfType(val nth: Nth) : PseudoClass("nth-of-type") {
+            override fun argsStr() = "$nth"
+        }
+        class NthLastOfType(val nth: Nth) : PseudoClass("nth-last-of-type") {
+            override fun argsStr() = "$nth"
+        }
+        class Host(val selector: CSSSelector) : PseudoClass("host") {
+            override fun argsStr() = "$selector"
+        }
+
+        // Etc
+        class Not(val selector: CSSSelector) : PseudoClass("not") {
+            override fun argsStr() = "$selector"
+        }
+    }
+
+    open class PseudoElement(val name: String) : CSSSelector() {
+        override fun equals(other: Any?): Boolean {
+            return if (other is PseudoElement) {
+                name == other.name && argsStr() == other.argsStr()
+            } else false
+        }
+        open fun argsStr(): String? = null
+        override fun toString(): String = "::$name${argsStr()?.let { "($it)" } ?: ""}"
+
+        companion object {
+            val after = PseudoElement("after")
+            val before = PseudoElement("before")
+            val cue = PseudoElement("cue")
+            val cueRegion = PseudoElement("cue-region")
+            val firstLetter = PseudoElement("first-letter")
+            val firstLine = PseudoElement("first-line")
+            val fileSelectorButton = PseudoElement("file-selector-button")
+            val selection = PseudoElement("selection")
+        }
+
+        class Slotted(val selector: CSSSelector) : PseudoElement("slotted") {
+            override fun argsStr() = selector.toString()
+        }
+    }
+}
+
+fun selector(selector: String) = CSSSelector.Raw(selector)
+fun combine(vararg selectors: CSSSelector) = CSSSelector.Combine(selectors.toMutableList())
+operator fun CSSSelector.plus(selector: CSSSelector) = combine(this, selector)
+operator fun String.plus(selector: CSSSelector) = combine(selector(this), selector)
+operator fun CSSSelector.plus(selector: String) = combine(this, selector(selector))
+operator fun CSSSelector.Combine.plus(selector: CSSSelector) { this.selectors.add(selector) }
+operator fun CSSSelector.Combine.plus(selector: String) { this.selectors.add(selector(selector)) }
+
+fun universal() = CSSSelector.Universal
+fun type(type: String) = CSSSelector.Type(type)
+fun className(className: String) = CSSSelector.CSSClass(className)
+fun id(id: String) = CSSSelector.Id(id)
+fun attr(
+    name: String,
+    value: String? = null,
+    operator: CSSSelector.Attribute.Operator = CSSSelector.Attribute.Operator.Equals,
+    caseSensitive: Boolean = true
+) = CSSSelector.Attribute(name, value, operator, caseSensitive)
+fun group(vararg selectors: CSSSelector) = CSSSelector.Group(selectors.toList())
+fun descendant(parent: CSSSelector, selected: CSSSelector) =
+    CSSSelector.Descendant(parent, selected)
+fun child(parent: CSSSelector, selected: CSSSelector) =
+    CSSSelector.Child(parent, selected)
+fun sibling(sibling: CSSSelector, selected: CSSSelector) = CSSSelector.Descendant(sibling, selected)
+fun adjacent(sibling: CSSSelector, selected: CSSSelector) = CSSSelector.Adjacent(sibling, selected)
+
+fun not(selector: CSSSelector) = CSSSelector.PseudoClass.Not(selector)
+fun hover() = CSSSelector.PseudoClass.hover
+fun hover(selector: CSSSelector) = selector + hover()

web/core/src/jsMain/kotlin/androidx/compose/web/elements/Base.kt

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.elements
+
+import androidx.compose.runtime.Applier
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.ComposeCompilerApi
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.DisposableEffectResult
+import androidx.compose.runtime.DisposableEffectScope
+import androidx.compose.runtime.ExplicitGroupsComposable
+import androidx.compose.runtime.SkippableUpdater
+import androidx.compose.runtime.currentComposer
+import androidx.compose.runtime.remember
+import androidx.compose.web.DomApplier
+import androidx.compose.web.DomNodeWrapper
+import androidx.compose.web.attributes.AttrsBuilder
+import androidx.compose.web.attributes.Tag
+import androidx.compose.web.css.StyleBuilder
+import androidx.compose.web.css.StyleBuilderImpl
+import kotlinx.browser.document
+import org.w3c.dom.HTMLElement
+
+@OptIn(ComposeCompilerApi::class)
+@Composable
+@ExplicitGroupsComposable
+inline fun <TScope, T, reified E : Applier<*>> ComposeDomNode(
+    noinline factory: () -> T,
+    elementScope: TScope,
+    noinline attrsSkippableUpdate: @Composable SkippableUpdater<T>.() -> Unit,
+    noinline styleSkippableUpdate: @Composable SkippableUpdater<T>.() -> Unit,
+    content: @Composable TScope.() -> Unit
+) {
+    if (currentComposer.applier !is E) error("Invalid applier")
+    currentComposer.startNode()
+    if (currentComposer.inserting) {
+        currentComposer.createNode(factory)
+    } else {
+        currentComposer.useNode()
+    }
+//    Updater<T>(currentComposer).update()
+    SkippableUpdater<T>(currentComposer).apply {
+        attrsSkippableUpdate()
+        styleSkippableUpdate()
+    }
+    currentComposer.startReplaceableGroup(0x7ab4aae9)
+    content(elementScope)
+    currentComposer.endReplaceableGroup()
+    currentComposer.endNode()
+}
+
+class DisposableEffectHolder(
+    var effect: (DisposableEffectScope.(HTMLElement) -> DisposableEffectResult)? = null
+)
+
+@Composable
+inline fun <TTag : Tag, THTMLElement : HTMLElement> TagElement(
+    tagName: String,
+    crossinline applyAttrs: AttrsBuilder<TTag>.() -> Unit,
+    crossinline applyStyle: StyleBuilder.() -> Unit,
+    content: @Composable ElementScope<THTMLElement>.() -> Unit
+) {
+    val scope = remember { ElementScopeImpl<THTMLElement>() }
+    val refEffect = remember { DisposableEffectHolder() }
+
+    ComposeDomNode<ElementScope<THTMLElement>, DomNodeWrapper, DomApplier>(
+        factory = {
+            DomNodeWrapper(document.createElement(tagName)).also {
+                scope.element = it.node.unsafeCast<THTMLElement>()
+            }
+        },
+        attrsSkippableUpdate = {
+            val attrsApplied = AttrsBuilder<TTag>().also { it.applyAttrs() }
+            refEffect.effect = attrsApplied.refEffect
+            val attrsCollected = attrsApplied.collect()
+            val events = attrsApplied.asList()
+
+            update {
+                set(attrsCollected, DomNodeWrapper.UpdateAttrs)
+                set(events, DomNodeWrapper.UpdateListeners)
+                set(attrsApplied.propertyUpdates, DomNodeWrapper.UpdateProperties)
+            }
+        },
+        styleSkippableUpdate = {
+            val style = StyleBuilderImpl().apply(applyStyle)
+            update {
+                set(style, DomNodeWrapper.UpdateStyleDeclarations)
+            }
+        },
+        elementScope = scope,
+        content = content
+    )
+
+    DisposableEffect(null) {
+        refEffect.effect?.invoke(this, scope.element) ?: onDispose {}
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/elements/ElementScope.kt

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.elements
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.ComposeCompilerApi
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.DisposableEffectResult
+import androidx.compose.runtime.DisposableEffectScope
+import androidx.compose.runtime.NonRestartableComposable
+import androidx.compose.runtime.RememberObserver
+import androidx.compose.runtime.SideEffect
+import androidx.compose.runtime.currentComposer
+import androidx.compose.runtime.remember
+import org.w3c.dom.HTMLElement
+
+interface DOMScope<out THTMLElement : HTMLElement>
+
+interface ElementScope<out THTMLElement : HTMLElement> : DOMScope<THTMLElement> {
+
+    @Composable
+    @NonRestartableComposable
+    fun DisposableRefEffect(
+        key: Any?,
+        effect: DisposableEffectScope.(THTMLElement) -> DisposableEffectResult
+    )
+
+    @Composable
+    @NonRestartableComposable
+    fun DisposableRefEffect(
+        effect: DisposableEffectScope.(THTMLElement) -> DisposableEffectResult
+    ) {
+        DisposableRefEffect(null, effect)
+    }
+
+    @Composable
+    @NonRestartableComposable
+    fun DomSideEffect(key: Any?, effect: DomEffectScope.(THTMLElement) -> Unit)
+
+    @Composable
+    @NonRestartableComposable
+    fun DomSideEffect(effect: DomEffectScope.(THTMLElement) -> Unit)
+}
+
+abstract class ElementScopeBase<out THTMLElement : HTMLElement> : ElementScope<THTMLElement> {
+    abstract val element: THTMLElement
+
+    private var nextDisposableDomEffectKey = 0
+
+    @Composable
+    @NonRestartableComposable
+    override fun DisposableRefEffect(
+        key: Any?,
+        effect: DisposableEffectScope.(THTMLElement) -> DisposableEffectResult
+    ) {
+        DisposableEffect(key) { effect(element) }
+    }
+
+    @Composable
+    @NonRestartableComposable
+    @OptIn(ComposeCompilerApi::class)
+    override fun DomSideEffect(
+        key: Any?,
+        effect: DomEffectScope.(THTMLElement) -> Unit
+    ) {
+        val changed = currentComposer.changed(key)
+        val effectHolder = remember(key) {
+            DomDisposableEffectHolder(this)
+        }
+        SideEffect {
+            if (changed) effectHolder.effect(element)
+        }
+    }
+
+    @Composable
+    @NonRestartableComposable
+    override fun DomSideEffect(effect: DomEffectScope.(THTMLElement) -> Unit) {
+        DomSideEffect(nextDisposableDomEffectKey++, effect)
+    }
+}
+
+open class ElementScopeImpl<THTMLElement : HTMLElement> : ElementScopeBase<THTMLElement>() {
+    public override lateinit var element: THTMLElement
+}
+
+interface DomEffectScope {
+    fun onDispose(disposeEffect: (HTMLElement) -> Unit)
+}
+
+private class DomDisposableEffectHolder(
+    val elementScope: ElementScopeBase<HTMLElement>
+) : RememberObserver, DomEffectScope {
+    var onDispose: ((HTMLElement) -> Unit)? = null
+
+    override fun onRemembered() {}
+
+    override fun onForgotten() {
+        onDispose?.invoke(elementScope.element)
+    }
+
+    override fun onAbandoned() {}
+
+    override fun onDispose(disposeEffect: (HTMLElement) -> Unit) {
+        onDispose = disposeEffect
+    }
+}

web/core/src/jsMain/kotlin/androidx/compose/web/elements/Elements.kt

@@ -0,0 +1,577 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.elements
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.ComposeNode
+import androidx.compose.web.DomApplier
+import androidx.compose.web.DomNodeWrapper
+import androidx.compose.web.attributes.AttrsBuilder
+import androidx.compose.web.attributes.InputType
+import androidx.compose.web.attributes.Tag
+import androidx.compose.web.attributes.action
+import androidx.compose.web.attributes.alt
+import androidx.compose.web.attributes.forId
+import androidx.compose.web.attributes.href
+import androidx.compose.web.attributes.label
+import androidx.compose.web.attributes.src
+import androidx.compose.web.attributes.type
+import androidx.compose.web.attributes.value
+import androidx.compose.web.css.StyleBuilder
+import kotlinx.browser.document
+import org.w3c.dom.HTMLAnchorElement
+import org.w3c.dom.HTMLBRElement
+import org.w3c.dom.HTMLDivElement
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.HTMLFormElement
+import org.w3c.dom.HTMLHeadingElement
+import org.w3c.dom.HTMLImageElement
+import org.w3c.dom.HTMLInputElement
+import org.w3c.dom.HTMLLIElement
+import org.w3c.dom.HTMLOListElement
+import org.w3c.dom.HTMLOptGroupElement
+import org.w3c.dom.HTMLOptionElement
+import org.w3c.dom.HTMLParagraphElement
+import org.w3c.dom.HTMLPreElement
+import org.w3c.dom.HTMLSelectElement
+import org.w3c.dom.HTMLSpanElement
+import org.w3c.dom.HTMLTableCaptionElement
+import org.w3c.dom.HTMLTableCellElement
+import org.w3c.dom.HTMLTableColElement
+import org.w3c.dom.HTMLTableElement
+import org.w3c.dom.HTMLTableRowElement
+import org.w3c.dom.HTMLTableSectionElement
+import org.w3c.dom.HTMLTextAreaElement
+import org.w3c.dom.HTMLUListElement
+import org.w3c.dom.Text
+
+@Composable
+fun Text(value: String) {
+    ComposeNode<DomNodeWrapper, DomApplier>(
+        factory = { DomNodeWrapper(document.createTextNode("")) },
+        update = {
+            set(value) { value -> (node as Text).data = value }
+        },
+    )
+}
+
+@Composable
+inline fun Div(
+    crossinline attrs: (AttrsBuilder<Tag.Div>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLDivElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "div",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun A(
+    href: String? = null,
+    crossinline attrs: (AttrsBuilder<Tag.A>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLAnchorElement>.() -> Unit
+) {
+    TagElement<Tag.A, HTMLAnchorElement>(
+        tagName = "a",
+        applyAttrs = {
+            href(href)
+            attrs()
+        },
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Input(
+    type: InputType = InputType.Text,
+    value: String = "",
+    crossinline attrs: (AttrsBuilder<Tag.Input>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLInputElement>.() -> Unit = {}
+) {
+    TagElement<Tag.Input, HTMLInputElement>(
+        tagName = "input",
+        applyAttrs = {
+            type(type)
+            value(value)
+            attrs()
+        },
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Button(
+    crossinline attrs: AttrsBuilder<Tag.Button>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("button", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun H1(
+    crossinline attrs: AttrsBuilder<Tag.H>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("h1", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun H2(
+    crossinline attrs: AttrsBuilder<Tag.H>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("h2", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun H3(
+    crossinline attrs: AttrsBuilder<Tag.H>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("h3", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun H4(
+    crossinline attrs: AttrsBuilder<Tag.H>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("h4", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun H5(
+    crossinline attrs: AttrsBuilder<Tag.H>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("h5", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun H6(
+    crossinline attrs: AttrsBuilder<Tag.H>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLHeadingElement>.() -> Unit
+) = TagElement("h6", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun P(
+    crossinline attrs: AttrsBuilder<Tag.P>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLParagraphElement>.() -> Unit
+) = TagElement("p", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Em(
+    crossinline attrs: AttrsBuilder<Tag>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) = TagElement("em", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun I(
+    crossinline attrs: AttrsBuilder<Tag>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) = TagElement("i", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun B(
+    crossinline attrs: AttrsBuilder<Tag>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) = TagElement("b", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Small(
+    crossinline attrs: AttrsBuilder<Tag>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) = TagElement("small", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Span(
+    crossinline attrs: AttrsBuilder<Tag.Span>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLSpanElement>.() -> Unit
+) = TagElement("span", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Br(
+    crossinline attrs: AttrsBuilder<Tag.Br>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLBRElement>.() -> Unit
+) = TagElement("br", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Ul(
+    crossinline attrs: AttrsBuilder<Tag.Ul>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLUListElement>.() -> Unit,
+) = TagElement("ul", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Ol(
+    crossinline attrs: AttrsBuilder<Tag.Ol>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLOListElement>.() -> Unit
+) = TagElement("ol", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun DOMScope<HTMLOListElement>.Li(
+    crossinline attrs: AttrsBuilder<Tag.Li>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLLIElement>.() -> Unit
+) = TagElement("li", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun DOMScope<HTMLUListElement>.Li(
+    crossinline attrs: AttrsBuilder<Tag.Li>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLLIElement>.() -> Unit
+) = TagElement("li", applyAttrs = attrs, applyStyle = style, content = content)
+
+@Composable
+inline fun Img(
+    src: String,
+    alt: String = "",
+    crossinline attrs: AttrsBuilder<Tag.Img>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLImageElement>.() -> Unit = {}
+) = TagElement<Tag.Img, HTMLImageElement>(
+    tagName = "img",
+    applyAttrs = {
+        src(src).alt(alt)
+        attrs()
+    },
+    applyStyle = style, content = content
+)
+
+@Composable
+inline fun Form(
+    action: String? = null,
+    crossinline attrs: AttrsBuilder<Tag.Form>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLFormElement>.() -> Unit
+) = TagElement<Tag.Form, HTMLFormElement>(
+    tagName = "form",
+    applyAttrs = {
+        if (!action.isNullOrEmpty()) action(action)
+        attrs()
+    },
+    applyStyle = style, content = content
+)
+
+@Composable
+inline fun Select(
+    crossinline attrs: AttrsBuilder<Tag.Select>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLSelectElement>.() -> Unit
+) = TagElement(
+    tagName = "select",
+    applyAttrs = attrs,
+    applyStyle = style,
+    content = content
+)
+
+@Composable
+inline fun DOMScope<HTMLUListElement>.Option(
+    value: String,
+    crossinline attrs: AttrsBuilder<Tag.Option>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLOptionElement>.() -> Unit
+) = TagElement<Tag.Option, HTMLOptionElement>(
+    tagName = "option",
+    applyAttrs = {
+        value(value)
+        attrs()
+    },
+    applyStyle = style,
+    content = content
+)
+
+@Composable
+inline fun OptGroup(
+    label: String,
+    crossinline attrs: AttrsBuilder<Tag.OptGroup>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLOptGroupElement>.() -> Unit
+) = TagElement<Tag.OptGroup, HTMLOptGroupElement>(
+    tagName = "optgroup",
+    applyAttrs = {
+        label(label)
+        attrs()
+    },
+    applyStyle = style,
+    content = content
+)
+
+@Composable
+inline fun Section(
+    crossinline attrs: AttrsBuilder<Tag>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) = TagElement(
+    tagName = "section",
+    applyAttrs = attrs,
+    applyStyle = style,
+    content = content
+)
+
+@Composable
+inline fun TextArea(
+    crossinline attrs: AttrsBuilder<Tag.TextArea>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    value: String
+) = TagElement<Tag.TextArea, HTMLTextAreaElement>(
+    tagName = "textarea",
+    applyAttrs = {
+        value(value)
+        attrs()
+    },
+    applyStyle = style
+) {
+    Text(value)
+}
+
+@Composable
+inline fun Nav(
+    crossinline attrs: AttrsBuilder<Tag.Nav>.() -> Unit = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) = TagElement(
+    tagName = "nav",
+    applyAttrs = attrs,
+    applyStyle = style,
+    content = content
+)
+
+@Composable
+inline fun Pre(
+    crossinline attrs: (AttrsBuilder<Tag.Pre>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLPreElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "pre",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Code(
+    crossinline attrs: (AttrsBuilder<Tag.Code>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "code",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Main(
+    crossinline attrs: (AttrsBuilder<Tag.Div>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit = {}
+) {
+    TagElement<Tag.Div, HTMLAnchorElement>(
+        tagName = "main",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Footer(
+    crossinline attrs: (AttrsBuilder<Tag.Div>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit = {}
+) {
+    TagElement<Tag.Div, HTMLAnchorElement>(
+        tagName = "footer",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Label(
+    forId: String? = null,
+    crossinline attrs: (AttrsBuilder<Tag.Label>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLElement>.() -> Unit = {}
+) {
+    TagElement<Tag.Label, HTMLAnchorElement>(
+        tagName = "label",
+        applyAttrs = {
+            forId(forId)
+            attrs()
+        },
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Table(
+    crossinline attrs: (AttrsBuilder<Tag.Table>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "table",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Caption(
+    crossinline attrs: (AttrsBuilder<Tag.Caption>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableCaptionElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "caption",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Col(
+    crossinline attrs: (AttrsBuilder<Tag.Col>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableColElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "col",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Colgroup(
+    crossinline attrs: (AttrsBuilder<Tag.Colgroup>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableColElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "colgroup",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Tr(
+    crossinline attrs: (AttrsBuilder<Tag.Tr>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableRowElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "tr",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Thead(
+    crossinline attrs: (AttrsBuilder<Tag.Thead>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableSectionElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "thead",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Th(
+    crossinline attrs: (AttrsBuilder<Tag.Th>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableCellElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "th",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Td(
+    crossinline attrs: (AttrsBuilder<Tag.Td>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableCellElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "td",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Tbody(
+    crossinline attrs: (AttrsBuilder<Tag.Tbody>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableSectionElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "tbody",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}
+
+@Composable
+inline fun Tfoot(
+    crossinline attrs: (AttrsBuilder<Tag.Tfoot>.() -> Unit) = {},
+    crossinline style: (StyleBuilder.() -> Unit) = {},
+    content: @Composable ElementScope<HTMLTableSectionElement>.() -> Unit
+) {
+    TagElement(
+        tagName = "tfoot",
+        applyAttrs = attrs,
+        applyStyle = style,
+        content = content
+    )
+}

web/core/src/jsMain/kotlin/androidx/compose/web/elements/Style.kt

@@ -0,0 +1,155 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.elements
+
+import androidx.compose.runtime.Composable
+import androidx.compose.web.attributes.AttrsBuilder
+import androidx.compose.web.attributes.Tag
+import androidx.compose.web.css.CSSGroupingRuleDeclaration
+import androidx.compose.web.css.CSSRuleDeclaration
+import androidx.compose.web.css.CSSRuleDeclarationList
+import androidx.compose.web.css.CSSStyleRuleDeclaration
+import androidx.compose.web.css.StylePropertyMap
+import androidx.compose.web.css.StylePropertyValue
+import androidx.compose.web.css.StyleSheetBuilder
+import androidx.compose.web.css.StyleSheetBuilderImpl
+import androidx.compose.web.css.cssRules
+import androidx.compose.web.css.deleteRule
+import androidx.compose.web.css.get
+import androidx.compose.web.css.insertRule
+import androidx.compose.web.css.styleMap
+import org.w3c.dom.HTMLStyleElement
+import org.w3c.dom.css.CSSGroupingRule
+import org.w3c.dom.css.CSSRule
+import org.w3c.dom.css.CSSStyleDeclaration
+import org.w3c.dom.css.CSSStyleRule
+import org.w3c.dom.css.StyleSheet
+
+/**
+ * Use this function to mount the <style> tag into the DOM tree.
+ *
+ * @param rulesBuild allows to define the style rules using [StyleSheetBuilder]
+ */
+@Composable
+inline fun Style(
+    crossinline applyAttrs: AttrsBuilder<Tag.Style>.() -> Unit = {},
+    rulesBuild: StyleSheetBuilder.() -> Unit
+) {
+    val builder = StyleSheetBuilderImpl()
+    builder.rulesBuild()
+    Style(applyAttrs, builder.cssRules)
+}
+
+/**
+ * Use this function to mount the <style> tag into the DOM tree.
+ *
+ * @param cssRules - is a list of style rules.
+ * Usually, it's [androidx.compose.web.css.StyleSheet] instance
+ */
+@Composable
+inline fun Style(
+    crossinline applyAttrs: AttrsBuilder<Tag.Style>.() -> Unit = {},
+    cssRules: CSSRuleDeclarationList
+) {
+    TagElement<Tag.Style, HTMLStyleElement>(
+        tagName = "style",
+        applyAttrs = {
+            applyAttrs()
+        },
+        applyStyle = {}
+    ) {
+        DomSideEffect(cssRules) { style ->
+            style.sheet?.let { sheet ->
+                setCSSRules(sheet, cssRules)
+                onDispose {
+                    clearCSSRules(sheet)
+                }
+            }
+        }
+    }
+}
+
+fun clearCSSRules(sheet: StyleSheet) {
+    repeat(sheet.cssRules.length) {
+        sheet.deleteRule(0)
+    }
+}
+
+fun setCSSRules(sheet: StyleSheet, cssRules: CSSRuleDeclarationList) {
+    cssRules.forEach { cssRule ->
+        sheet.addRule(cssRule)
+    }
+}
+
+private fun StyleSheet.addRule(cssRule: String): CSSRule {
+    val cssRuleIndex = this.insertRule(cssRule, this.cssRules.length)
+    return this.cssRules[cssRuleIndex]
+}
+
+private fun CSSGroupingRule.addRule(cssRule: String): CSSRule {
+    val cssRuleIndex = this.insertRule(cssRule, this.cssRules.length)
+    return this.cssRules[cssRuleIndex]
+}
+
+private fun StyleSheet.addRule(cssRuleDeclaration: CSSRuleDeclaration) {
+    val cssRule = addRule("${cssRuleDeclaration.header} {}")
+    fillRule(cssRuleDeclaration, cssRule)
+}
+
+private fun CSSGroupingRule.addRule(cssRuleDeclaration: CSSRuleDeclaration) {
+    val cssRule = addRule("${cssRuleDeclaration.header} {}")
+    fillRule(cssRuleDeclaration, cssRule)
+}
+
+private fun fillRule(
+    cssRuleDeclaration: CSSRuleDeclaration,
+    cssRule: CSSRule
+) {
+    when (cssRuleDeclaration) {
+        is CSSStyleRuleDeclaration -> {
+            val cssStyleRule = cssRule.unsafeCast<CSSStyleRule>()
+            cssRuleDeclaration.style.properties.forEach { (name, value) ->
+                setProperty(cssStyleRule.styleMap, name, value)
+            }
+            cssRuleDeclaration.style.variables.forEach { (name, value) ->
+                setVariable(cssStyleRule.style, name, value)
+            }
+        }
+        is CSSGroupingRuleDeclaration -> {
+            val cssGroupingRule = cssRule.unsafeCast<CSSGroupingRule>()
+            cssRuleDeclaration.rules.forEach { childRuleDeclaration ->
+                cssGroupingRule.addRule(childRuleDeclaration)
+            }
+        }
+    }
+}
+
+fun setProperty(
+    styleMap: StylePropertyMap,
+    name: String,
+    value: StylePropertyValue
+) {
+    styleMap.set(name, value)
+}
+
+fun setVariable(
+    style: CSSStyleDeclaration,
+    name: String,
+    value: StylePropertyValue
+) {
+    style.setProperty("--$name", value.toString())
+}

web/core/src/jsMain/kotlin/androidx/compose/web/events/WrappedEvent.kt

@@ -0,0 +1,123 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.web.events
+
+import org.w3c.dom.DragEvent
+import org.w3c.dom.TouchEvent
+import org.w3c.dom.clipboard.ClipboardEvent
+import org.w3c.dom.events.CompositionEvent
+import org.w3c.dom.events.Event
+import org.w3c.dom.events.FocusEvent
+import org.w3c.dom.events.InputEvent
+import org.w3c.dom.events.KeyboardEvent
+import org.w3c.dom.events.MouseEvent
+import org.w3c.dom.events.WheelEvent
+import org.w3c.dom.pointerevents.PointerEvent
+
+interface GenericWrappedEvent<T : Event> {
+    val nativeEvent: T
+}
+
+interface WrappedEvent : GenericWrappedEvent<Event>
+
+open class WrappedMouseEvent(
+    override val nativeEvent: MouseEvent
+) : GenericWrappedEvent<MouseEvent> {
+
+    // MouseEvent doesn't support movementX and movementY on IE6-11, and it's OK for now.
+    val movementX: Double
+        get() = nativeEvent.asDynamic().movementX as Double
+    val movementY: Double
+        get() = nativeEvent.asDynamic().movementY as Double
+}
+
+open class WrappedWheelEvent(
+    override val nativeEvent: WheelEvent
+) : GenericWrappedEvent<WheelEvent>
+
+open class WrappedInputEvent(
+    override val nativeEvent: InputEvent
+) : GenericWrappedEvent<InputEvent>
+
+open class WrappedKeyboardEvent(
+    override val nativeEvent: KeyboardEvent
+) : GenericWrappedEvent<KeyboardEvent> {
+
+    fun getNormalizedKey(): String = nativeEvent.key.let {
+        normalizedKeys[it] ?: it
+    }
+
+    companion object {
+        private val normalizedKeys = mapOf(
+            "Esc" to "Escape",
+            "Spacebar" to " ",
+            "Left" to "ArrowLeft",
+            "Up" to "ArrowUp",
+            "Right" to "ArrowRight",
+            "Down" to "ArrowDown",
+            "Del" to "Delete",
+            "Apps" to "ContextMenu",
+            "Menu" to "ContextMenu",
+            "Scroll" to "ScrollLock",
+            "MozPrintableKey" to "Unidentified",
+        )
+        // Firefox bug for Windows key https://bugzilla.mozilla.org/show_bug.cgi?id=1232918
+    }
+}
+
+open class WrappedFocusEvent(
+    override val nativeEvent: FocusEvent
+) : GenericWrappedEvent<FocusEvent>
+
+open class WrappedTouchEvent(
+    override val nativeEvent: TouchEvent
+) : GenericWrappedEvent<TouchEvent>
+
+open class WrappedCompositionEvent(
+    override val nativeEvent: CompositionEvent
+) : GenericWrappedEvent<CompositionEvent>
+
+open class WrappedDragEvent(
+    override val nativeEvent: DragEvent
+) : GenericWrappedEvent<DragEvent>
+
+open class WrappedPointerEvent(
+    override val nativeEvent: PointerEvent
+) : GenericWrappedEvent<PointerEvent>
+
+open class WrappedClipboardEvent(
+    override val nativeEvent: ClipboardEvent
+) : GenericWrappedEvent<ClipboardEvent>
+
+class WrappedTextInputEvent(
+    nativeEvent: InputEvent,
+    val inputValue: String
+) : WrappedInputEvent(nativeEvent)
+
+class WrappedCheckBoxInputEvent(
+    override val nativeEvent: Event,
+    val checked: Boolean
+) : GenericWrappedEvent<Event>
+
+class WrappedRadioInputEvent(
+    override val nativeEvent: Event,
+    val checked: Boolean
+) : GenericWrappedEvent<Event>
+
+class WrappedEventImpl(
+    override val nativeEvent: Event
+) : WrappedEvent

web/core/src/jsMain/kotlin/withWeb/Modifier.kt

@@ -0,0 +1,47 @@
+package org.jetbrains.compose.common.ui
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.core.graphics.Color
+import androidx.compose.web.css.backgroundColor
+import androidx.compose.web.css.margin
+import androidx.compose.web.css.px
+import androidx.compose.web.css.Color.RGB
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.StyleBuilder
+import androidx.compose.web.attributes.AttrsBuilder
+
+actual fun Modifier.background(color: Color): Modifier = castOrCreate().apply {
+    add {
+        backgroundColor(RGB(color.red, color.green, color.blue))
+    }
+}
+
+fun Modifier.asStyleBuilderApplier(
+    passThroughHandler: (StyleBuilder.() -> Unit)? = null
+): StyleBuilder.() -> Unit = castOrCreate().let { modifier ->
+    val st: StyleBuilder.() -> Unit = {
+        modifier.styleHandlers.forEach { it.invoke(this) }
+        passThroughHandler?.invoke(this)
+    }
+
+    st
+}
+
+fun Modifier.asAttributeBuilderApplier(
+    passThroughHandler: (AttrsBuilder<*>.() -> Unit)? = null
+): AttrsBuilder<*>.() -> Unit =
+    castOrCreate().let { modifier ->
+        val st: AttrsBuilder<*>.() -> Unit = {
+            modifier.attrHandlers.forEach { it.invoke(this) }
+            passThroughHandler?.invoke(this)
+        }
+
+        st
+    }
+
+actual fun Modifier.padding(all: Dp): Modifier = castOrCreate().apply {
+    // yes, it's not a typo, what Modifier.padding does is actually adding marginEe
+    add {
+        margin(all.value.px)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/Styles.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.web.ui
+
+import androidx.compose.web.css.justifyContent
+import androidx.compose.web.css.JustifyContent
+import androidx.compose.web.css.alignItems
+import androidx.compose.web.css.AlignItems
+import androidx.compose.web.css.flexDirection
+import androidx.compose.web.css.FlexDirection
+import androidx.compose.web.css.display
+import androidx.compose.web.css.DisplayStyle
+import androidx.compose.web.css.left
+import androidx.compose.web.css.px
+
+import androidx.compose.web.css.StyleSheet
+
+object Styles : StyleSheet() {
+    val columnClass = "compose-web-column"
+
+    val textClass by style {
+        display(DisplayStyle.Block)
+        left(0.px)
+    }
+
+    val rowClass by style {
+        display(DisplayStyle.Flex)
+        flexDirection(FlexDirection.Row)
+    }
+
+    val composeWebArrangementHorizontalStart by style {
+        justifyContent(JustifyContent.FlexStart)
+    }
+
+    val composeWebArrangementHorizontalEnd by style {
+        justifyContent(JustifyContent.FlexEnd)
+    }
+
+    val composeWebAlignmentVerticalTop by style {
+        alignItems(AlignItems.FlexStart)
+    }
+
+    val composeWebAlignmentVerticalCenter by style {
+        alignItems(AlignItems.Center)
+    }
+
+    val composeWebAlignmentVerticalBottom by style {
+        alignItems(AlignItems.FlexEnd)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/internal/ActualModifier.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.internal
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.web.css.StyleBuilder
+import androidx.compose.web.attributes.AttrsBuilder
+
+class ActualModifier : Modifier {
+    val styleHandlers = mutableListOf<StyleBuilder.() -> Unit>()
+    val attrHandlers = mutableListOf<AttrsBuilder<*>.() -> Unit>()
+
+    fun add(builder: StyleBuilder.() -> Unit) {
+        styleHandlers.add(builder)
+    }
+
+    fun addAttributeBuilder(builder: AttrsBuilder<*>.() -> Unit) {
+        attrHandlers.add(builder)
+    }
+}
+
+fun Modifier.castOrCreate(): ActualModifier = (this as? ActualModifier) ?: ActualModifier()

web/core/src/jsMain/kotlin/withWeb/layouts/box.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.asStyleBuilderApplier
+import androidx.compose.runtime.Composable
+import androidx.compose.web.elements.Div
+import org.jetbrains.compose.common.ui.asAttributeBuilderApplier
+
+@Composable
+internal actual fun BoxActual(modifier: Modifier, content: @Composable () -> Unit) {
+    Div(
+        style = modifier.asStyleBuilderApplier(),
+        attrs = modifier.asAttributeBuilderApplier()
+    ) {
+        content()
+    }
+}

web/core/src/jsMain/kotlin/withWeb/layouts/button.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import androidx.compose.web.elements.Button
+import org.jetbrains.compose.common.ui.asStyleBuilderApplier
+
+@Composable
+actual fun ButtonActual(
+    modifier: Modifier,
+    onClick: () -> Unit,
+    content: @Composable () -> Unit
+) {
+    Button(
+        style = modifier.asStyleBuilderApplier(),
+        attrs = {
+            onClick { onClick() }
+        }
+    ) {
+        content()
+    }
+}

web/core/src/jsMain/kotlin/withWeb/layouts/column.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.asStyleBuilderApplier
+import androidx.compose.web.elements.Div
+import org.jetbrains.compose.web.ui.Styles
+
+@Composable
+internal actual fun ColumnActual(modifier: Modifier, content: @Composable () -> Unit) {
+    Div(
+        attrs = {
+            classes(Styles.columnClass)
+        },
+        style = modifier.asStyleBuilderApplier()
+    ) {
+        content()
+    }
+}

web/core/src/jsMain/kotlin/withWeb/layouts/row.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import androidx.compose.web.elements.Div
+import org.jetbrains.compose.common.ui.asStyleBuilderApplier
+import org.jetbrains.compose.common.ui.Alignment
+import org.jetbrains.compose.web.ui.Styles
+
+private fun Arrangement.Horizontal.asClassName() = when (this) {
+    Arrangement.End -> Styles.composeWebArrangementHorizontalEnd
+    else -> Styles.composeWebArrangementHorizontalStart
+}
+
+private fun Alignment.Vertical.asClassName() = when (this) {
+    Alignment.Top -> Styles.composeWebAlignmentVerticalTop
+    Alignment.CenterVertically -> Styles.composeWebAlignmentVerticalCenter
+    else -> Styles.composeWebAlignmentVerticalBottom
+}
+
+@Composable
+internal actual fun RowActual(
+    modifier: Modifier,
+    horizontalArrangement: Arrangement.Horizontal,
+    verticalAlignment: Alignment.Vertical,
+    content: @Composable () -> Unit
+) {
+    Div(
+        attrs = {
+            classes(
+                *arrayOf(
+                    Styles.rowClass,
+                    horizontalArrangement.asClassName(),
+                    verticalAlignment.asClassName()
+                )
+            )
+        },
+        style = modifier.asStyleBuilderApplier()
+    ) {
+        content()
+    }
+}

web/core/src/jsMain/kotlin/withWeb/layouts/slider.kt

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.web.elements.Input
+import androidx.compose.web.attributes.InputType
+
+@Composable
+actual fun SliderActual(
+    value: Float,
+    onValueChange: (Float) -> Unit,
+    valueRange: ClosedFloatingPointRange<Float>,
+    steps: Int,
+    modifier: Modifier,
+) {
+    val stepCount = if (steps == 0) 100 else steps
+    val step = (valueRange.endInclusive - valueRange.start) / stepCount
+
+    Input(
+        type = InputType.Range,
+        value = value.toString(),
+        attrs = {
+            attr("min", valueRange.start.toString())
+            attr("max", valueRange.endInclusive.toString())
+            attr("step", step.toString())
+            onRangeInput {
+                val value: String = it.nativeEvent.target.asDynamic().value
+                onValueChange(value.toFloat())
+            }
+        }
+    ) {}
+}

web/core/src/jsMain/kotlin/withWeb/layouts/text.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import androidx.compose.web.elements.Text as TextNode
+import androidx.compose.web.elements.Span
+import org.jetbrains.compose.web.ui.Styles
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.asStyleBuilderApplier
+import org.jetbrains.compose.common.ui.asAttributeBuilderApplier
+import org.jetbrains.compose.common.core.graphics.Color
+import androidx.compose.web.css.color
+import androidx.compose.web.css.fontSize
+import androidx.compose.web.css.Color.RGB
+import org.jetbrains.compose.common.ui.unit.TextUnit
+import org.jetbrains.compose.common.ui.unit.TextUnitType
+import androidx.compose.web.css.em
+import androidx.compose.web.css.px
+
+@Composable
+actual fun TextActual(
+    text: String,
+    modifier: Modifier,
+    color: Color,
+    size: TextUnit
+) {
+    Span(
+        style = modifier.asStyleBuilderApplier() {
+            color(RGB(color.red, color.green, color.blue))
+            when (size.unitType) {
+                TextUnitType.Em -> fontSize(size.value.em)
+                TextUnitType.Sp -> fontSize(size.value.px)
+            }
+        },
+        attrs = modifier.asAttributeBuilderApplier() {
+            classes(Styles.textClass)
+        }
+    ) {
+        TextNode(text)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/border.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.px
+import androidx.compose.web.css.LineStyle
+import androidx.compose.web.css.border
+import androidx.compose.web.css.Color.RGB
+
+actual fun Modifier.border(size: Dp, color: Color): Modifier = castOrCreate().apply {
+    add {
+        border(size.value.px, LineStyle.Solid, RGB(color.red, color.green, color.blue))
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/clickable.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.internal.castOrCreate
+
+actual fun Modifier.clickable(onClick: () -> Unit): Modifier = castOrCreate().apply {
+    addAttributeBuilder {
+        onClick { onClick() }
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/clip.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.draw
+
+import org.jetbrains.compose.common.ui.Modifier
+import jetbrains.compose.common.shapes.Shape
+import jetbrains.compose.common.shapes.CircleShape
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.borderRadius
+import androidx.compose.web.css.percent
+
+actual fun Modifier.clip(shape: Shape): Modifier = castOrCreate().apply {
+    when (shape) {
+        CircleShape -> add {
+            borderRadius(50.percent)
+        }
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/fillMaxHeight.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.height
+import androidx.compose.web.css.percent
+
+actual fun Modifier.fillMaxHeight(fraction: Float): Modifier = castOrCreate().apply {
+    add {
+        height((100 * fraction).percent)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/fillMaxWidth.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.width
+import androidx.compose.web.css.percent
+
+actual fun Modifier.fillMaxWidth(): Modifier = castOrCreate().apply {
+    add {
+        width(100.percent)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/offset.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.marginTop
+import androidx.compose.web.css.marginLeft
+import androidx.compose.web.css.px
+
+actual fun Modifier.offset(x: Dp, y: Dp): Modifier = castOrCreate().apply {
+    add {
+        marginLeft(x.value.px)
+        marginTop(y.value.px)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/onSizeChanged.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.unit.IntSize
+
+actual fun Modifier.onSizeChanged(
+    onSizeChanged: (IntSize) -> Unit
+): Modifier {
+    return this
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/size.kt

@@ -0,0 +1,14 @@
+package org.jetbrains.compose.common.ui
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import androidx.compose.web.css.width
+import androidx.compose.web.css.height
+import androidx.compose.web.css.px
+import org.jetbrains.compose.common.internal.castOrCreate
+
+actual fun Modifier.size(width: Dp, height: Dp): Modifier = castOrCreate().apply {
+    add {
+        width(width.value.px)
+        height(height.value.px)
+    }
+}

web/core/src/jsMain/kotlin/withWeb/modifiers/width.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.web.css.px
+import androidx.compose.web.css.width
+
+actual fun Modifier.width(size: Dp): Modifier = castOrCreate().apply {
+    add {
+        width(size.value.px)
+    }
+}

web/core/src/jsMain/resources/index.html

@@ -0,0 +1,28 @@
+<!--
+  ~ Copyright 2021 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>compose-browser-demo</title>
+</head>
+<body>
+<h1>Hello world!</h1>
+<div id="root"/>
+<script src="web.js"></script>
+</body>
+</html>

web/core/src/jsTest/kotlin/DomSideEffectTests.kt

@@ -0,0 +1,126 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.web.elements.Div
+import androidx.compose.web.renderComposable
+import kotlinx.browser.document
+import kotlinx.dom.clear
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class DomSideEffectTests {
+
+    @Test
+    fun canCreateElementsInDomSideEffect() {
+        val root = "div".asHtmlElement()
+
+        renderComposable(
+            root = root
+        ) {
+            Div {
+                DomSideEffect {
+                    it.appendChild(
+                        document.createElement("p").also {
+                            it.appendChild(document.createTextNode("Hello World!"))
+                        }
+                    )
+                }
+            }
+        }
+        assertEquals(
+            expected = "<div><div style=\"\"><p>Hello World!</p></div></div>",
+            actual = root.outerHTML
+        )
+    }
+
+    @Test
+    fun canUpdateElementsCreatedInDomSideEffect() = runTest {
+        var i: Int by mutableStateOf(0)
+        val disposeCalls = mutableListOf<Int>()
+
+        @Composable
+        fun CustomDiv(value: Int) {
+            Div {
+                DomSideEffect(value) {
+                    it.appendChild(
+                        it.appendChild(document.createTextNode("Value = $value"))
+                    )
+                    onDispose {
+                        disposeCalls.add(value)
+                        it.clear()
+                    }
+                }
+            }
+        }
+
+        composition { CustomDiv(i) }
+
+        assertEquals(
+            expected = "<div><div style=\"\">Value = 0</div></div>",
+            actual = root.outerHTML
+        )
+
+        i = 1
+
+        waitChanges()
+        assertEquals(
+            expected = 1,
+            actual = disposeCalls.size,
+            message = "Only one onDispose call expected"
+        )
+        assertEquals(
+            expected = 0,
+            actual = disposeCalls[0],
+            message = "onDispose should be called with a previous value"
+        )
+        assertEquals(
+            expected = "<div><div style=\"\">Value = 1</div></div>",
+            actual = root.outerHTML
+        )
+    }
+
+    @Test
+    fun onDisposeIsCalledWhenComposableRemovedFromComposition() = runTest {
+        var showDiv: Boolean by mutableStateOf(true)
+        var onDisposeCalledTimes = 0
+
+        composition {
+            if (showDiv) {
+                Div {
+                    DomSideEffect {
+                        it.appendChild(document.createTextNode("Goedemorgen!"))
+                        onDispose { onDisposeCalledTimes++ }
+                    }
+                }
+            }
+        }
+
+        assertEquals(
+            expected = "<div><div style=\"\">Goedemorgen!</div></div>",
+            actual = root.outerHTML
+        )
+
+        showDiv = false
+
+        waitChanges()
+        assertEquals(1, onDisposeCalledTimes)
+        assertEquals(expected = "<div></div>", actual = root.outerHTML)
+    }
+}

web/core/src/jsTest/kotlin/InlineStyleTests.kt

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.setValue
+import androidx.compose.web.css.color
+import androidx.compose.web.elements.Span
+import androidx.compose.web.elements.Text
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class InlineStyleTests {
+
+    @Test
+    fun conditionalStyleAppliedProperly() = runTest {
+
+        var isRed by mutableStateOf(true)
+        composition {
+            Span(
+                style = {
+                    if (isRed) {
+                        color("red")
+                    } else {
+                        color("green")
+                    }
+                }
+            ) {
+                Text("text")
+            }
+        }
+
+        assertEquals(
+            expected = "<span style=\"color: red;\">text</span>",
+            actual = root.innerHTML
+        )
+
+        isRed = false
+        waitChanges()
+
+        assertEquals(
+            expected = "<span style=\"color: green;\">text</span>",
+            actual = root.innerHTML
+        )
+    }
+
+    @Test
+    fun conditionalStyleAddedWhenTrue() = runTest {
+        var isRed by mutableStateOf(false)
+        composition {
+            Span(
+                style = {
+                    if (isRed) {
+                        color("red")
+                    }
+                }
+            ) {
+                Text("text")
+            }
+        }
+
+        assertEquals(
+            expected = "<span style=\"\">text</span>",
+            actual = root.innerHTML
+        )
+
+        isRed = true
+        waitChanges()
+
+        assertEquals(
+            expected = "<span style=\"color: red;\">text</span>",
+            actual = root.innerHTML
+        )
+    }
+
+    @Test
+    fun conditionalStyleGetsRemovedWhenFalse() = runTest {
+        var isRed by mutableStateOf(true)
+        composition {
+            Span(
+                style = {
+                    if (isRed) {
+                        color("red")
+                    }
+                }
+            ) {
+                Text("text")
+            }
+        }
+
+        assertEquals(
+            expected = "<span style=\"color: red;\">text</span>",
+            actual = root.innerHTML
+        )
+
+        isRed = false
+        waitChanges()
+
+        assertEquals(
+            expected = "<span style=\"\">text</span>",
+            actual = root.innerHTML
+        )
+    }
+
+    @Test
+    fun conditionalStyleUpdatedProperly() = runTest {
+        var isRed by mutableStateOf(true)
+        composition {
+            Span(
+                style = {
+                    if (isRed) {
+                        color("red")
+                    }
+                }
+            ) {
+                Text("text")
+            }
+        }
+
+        assertEquals(
+            expected = "<span style=\"color: red;\">text</span>",
+            actual = root.innerHTML
+        )
+
+        repeat(4) {
+            isRed = !isRed
+            waitChanges()
+
+            val expected = if (isRed) {
+                "<span style=\"color: red;\">text</span>"
+            } else {
+                "<span style=\"\">text</span>"
+            }
+            assertEquals(
+                expected = expected,
+                actual = root.innerHTML
+            )
+        }
+    }
+}

web/core/src/jsTest/kotlin/StaticComposableTests.kt

@@ -0,0 +1,599 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import androidx.compose.web.css.AlignContent
+import androidx.compose.web.css.AlignItems
+import androidx.compose.web.css.AlignSelf
+import androidx.compose.web.css.Color
+import androidx.compose.web.css.DisplayStyle
+import androidx.compose.web.css.FlexDirection
+import androidx.compose.web.css.FlexWrap
+import androidx.compose.web.css.JustifyContent
+import androidx.compose.web.css.Position
+import androidx.compose.web.css.alignContent
+import androidx.compose.web.css.alignItems
+import androidx.compose.web.css.alignSelf
+import androidx.compose.web.css.border
+import androidx.compose.web.css.borderRadius
+import androidx.compose.web.css.bottom
+import androidx.compose.web.css.color
+import androidx.compose.web.css.display
+import androidx.compose.web.css.flexDirection
+import androidx.compose.web.css.flexFlow
+import androidx.compose.web.css.flexGrow
+import androidx.compose.web.css.flexShrink
+import androidx.compose.web.css.flexWrap
+import androidx.compose.web.css.height
+import androidx.compose.web.css.justifyContent
+import androidx.compose.web.css.left
+import androidx.compose.web.css.opacity
+import androidx.compose.web.css.order
+import androidx.compose.web.css.position
+import androidx.compose.web.css.px
+import androidx.compose.web.css.right
+import androidx.compose.web.css.top
+import androidx.compose.web.css.value
+import androidx.compose.web.css.width
+import androidx.compose.web.elements.Div
+import androidx.compose.web.elements.Span
+import androidx.compose.web.elements.Text
+import androidx.compose.web.renderComposable
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.get
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class StaticComposableTests {
+    @Test
+    fun emptyComposable() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {}
+        assertEquals("<div></div>", root.outerHTML)
+    }
+
+    @Test
+    fun textChild() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Text("inner text")
+        }
+        assertEquals("<div>inner text</div>", root.outerHTML)
+    }
+
+    @Test
+    fun attrs() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                attrs = {
+                    classes("some", "simple", "classes")
+                    id("special")
+                    attr("data-val", "some data")
+                    attr("data-val", "some other data")
+                    id("verySpecial")
+                }
+            ) {}
+        }
+
+        val el = root.firstChild
+        assertTrue(el is HTMLElement, "element not found")
+
+        assertEquals("verySpecial", el.getAttribute("id"))
+        assertEquals("some simple classes", el.getAttribute("class"))
+        assertEquals("some other data", el.getAttribute("data-val"))
+    }
+
+    @Test
+    fun styles() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    opacity(0.3)
+                    color("red")
+                    opacity(0.2)
+                    color("green")
+                }
+            ) {}
+        }
+
+        assertEquals("opacity: 0.2; color: green;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesBorder() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    property("border", value("1px solid red"))
+                }
+            ) {}
+            Div(
+                style = {
+                    border(3.px, color = Color("green"))
+                }
+            ) {}
+        }
+
+        assertEquals("border: 1px solid red;", (root.children[0] as HTMLElement).style.cssText)
+        root.children[1]?.let { el ->
+            assertEquals(
+                "green",
+                el.asDynamic().attributeStyleMap.get("border-color").toString(),
+            )
+            assertEquals(
+                "3px",
+                el.asDynamic().attributeStyleMap.get("border-width").toString(),
+            )
+        }
+    }
+
+    @Test
+    fun stylesOrder() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    order(-4)
+                }
+            ) {}
+            Div(
+                style = {
+                    order(3)
+                }
+            ) {}
+        }
+
+        assertEquals("order: -4;", (root.children[0] as HTMLElement).style.cssText)
+        assertEquals("order: 3;", (root.children[1] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesFlexGrow() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    flexGrow(3)
+                }
+            ) {}
+            Div(
+                style = {
+                    flexGrow(2.5)
+                }
+            ) {}
+            Div(
+                style = {
+                    flexGrow(1e2)
+                }
+            ) {}
+            Div(
+                style = {
+                    flexGrow(.6)
+                }
+            ) {}
+        }
+
+        assertEquals("flex-grow: 3;", (root.children[0] as HTMLElement).style.cssText)
+        assertEquals("flex-grow: 2.5;", (root.children[1] as HTMLElement).style.cssText)
+        assertEquals("flex-grow: 100;", (root.children[2] as HTMLElement).style.cssText)
+        assertEquals("flex-grow: 0.6;", (root.children[3] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesFlexShrink() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    flexShrink(3)
+                }
+            ) {}
+            Div(
+                style = {
+                    flexShrink(2.5)
+                }
+            ) {}
+            Div(
+                style = {
+                    flexShrink(1e2)
+                }
+            ) {}
+            Div(
+                style = {
+                    flexShrink(.6)
+                }
+            ) {}
+        }
+
+        assertEquals("flex-shrink: 3;", (root.children[0] as HTMLElement).style.cssText)
+        assertEquals("flex-shrink: 2.5;", (root.children[1] as HTMLElement).style.cssText)
+        assertEquals("flex-shrink: 100;", (root.children[2] as HTMLElement).style.cssText)
+        assertEquals("flex-shrink: 0.6;", (root.children[3] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesWidth() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    width(100.px)
+                }
+            ) {}
+        }
+
+        assertEquals("width: 100px;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesBorderRadius() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    borderRadius(3.px)
+                }
+            ) {}
+            Div(
+                style = {
+                    borderRadius(3.px, 5.px)
+                }
+            ) {}
+            Div(
+                style = {
+                    borderRadius(3.px, 5.px, 4.px)
+                }
+            ) {}
+            Div(
+                style = {
+                    borderRadius(3.px, 5.px, 4.px, 1.px)
+                }
+            ) {}
+        }
+
+        assertEquals("border-radius: 3px;", (root.children[0] as HTMLElement).style.cssText)
+        assertEquals("border-radius: 3px 5px;", (root.children[1] as HTMLElement).style.cssText)
+        assertEquals("border-radius: 3px 5px 4px;", (root.children[2] as HTMLElement).style.cssText)
+        assertEquals(
+            "border-radius: 3px 5px 4px 1px;",
+            (root.children[3] as HTMLElement).style.cssText
+        )
+    }
+
+    @Test
+    fun stylesTop() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    top(100.px)
+                }
+            ) {}
+        }
+
+        assertEquals("top: 100px;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesBottom() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    bottom(100.px)
+                }
+            ) {}
+        }
+
+        assertEquals("bottom: 100px;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesLeft() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    left(100.px)
+                }
+            ) {}
+        }
+
+        assertEquals("left: 100px;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesRight() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    right(100.px)
+                }
+            ) {}
+        }
+
+        assertEquals("right: 100px;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesHeight() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Div(
+                style = {
+                    height(100.px)
+                }
+            ) {}
+        }
+
+        assertEquals("height: 100px;", (root.children[0] as HTMLElement).style.cssText)
+    }
+
+    @Test
+    fun stylesDisplay() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<DisplayStyle>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { displayStyle ->
+                Div(
+                    style = {
+                        display(displayStyle)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, displayStyle ->
+            assertEquals(
+                "display: ${displayStyle.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesFlexDirection() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<FlexDirection>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { flexDirection ->
+                Span(
+                    style = {
+                        flexDirection(flexDirection)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, displayStyle ->
+            assertEquals(
+                "flex-direction: ${displayStyle.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesFlexWrap() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<FlexWrap>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { flexWrap ->
+                Span(
+                    style = {
+                        flexWrap(flexWrap)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, displayStyle ->
+            assertEquals(
+                "flex-wrap: ${displayStyle.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesFlexFlow() {
+        val root = "div".asHtmlElement()
+        val flexWraps = enumValues<FlexWrap>()
+        val flexDirections = enumValues<FlexDirection>()
+        renderComposable(
+            root = root
+        ) {
+            flexDirections.forEach { flexDirection ->
+                flexWraps.forEach { flexWrap ->
+                    Span(
+                        style = {
+                            flexFlow(flexDirection, flexWrap)
+                        }
+                    ) { }
+                }
+            }
+        }
+
+        flexDirections.forEachIndexed { i, flexDirection ->
+            flexWraps.forEachIndexed { j, flexWrap ->
+                assertEquals(
+                    "flex-flow: ${flexDirection.value} ${flexWrap.value};",
+                    (root.children[3 * i + j % 3] as HTMLElement).style.cssText
+                )
+            }
+        }
+    }
+
+    @Test
+    fun stylesJustifyContent() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<JustifyContent>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { justifyContent ->
+                Span(
+                    style = {
+                        justifyContent(justifyContent)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, justifyContent ->
+            assertEquals(
+                "justify-content: ${justifyContent.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesAlignSelf() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<AlignSelf>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { alignSelf ->
+                Span(
+                    style = {
+                        alignSelf(alignSelf)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, alignSelf ->
+            assertEquals(
+                "align-self: ${alignSelf.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesAlignItems() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<AlignItems>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { alignItems ->
+                Span(
+                    style = {
+                        alignItems(alignItems)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, alignItems ->
+            assertEquals(
+                "align-items: ${alignItems.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesAlignContent() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<AlignContent>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { alignContent ->
+                Span(
+                    style = {
+                        alignContent(alignContent)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, alignContent ->
+            assertEquals(
+                "align-content: ${alignContent.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+
+    @Test
+    fun stylesPosition() {
+        val root = "div".asHtmlElement()
+        val enumValues = enumValues<Position>()
+        renderComposable(
+            root = root
+        ) {
+            enumValues.forEach { position ->
+                Span(
+                    style = {
+                        position(position)
+                    }
+                ) { }
+            }
+        }
+
+        enumValues.forEachIndexed { index, position ->
+            assertEquals(
+                "position: ${position.value};",
+                (root.children[index] as HTMLElement).style.cssText
+            )
+        }
+    }
+}

web/core/src/jsTest/kotlin/TestUtils.kt

@@ -0,0 +1,94 @@
+import androidx.compose.runtime.Composable
+import androidx.compose.web.renderComposable
+import kotlinx.browser.document
+import kotlinx.browser.window
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.MainScope
+import kotlinx.coroutines.promise
+import kotlinx.dom.clear
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.MutationObserver
+import org.w3c.dom.MutationObserverInit
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
+
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+private val testScope = MainScope()
+
+class TestScope : CoroutineScope by testScope {
+
+    val root = "div".asHtmlElement()
+
+    fun composition(content: @Composable () -> Unit) {
+        root.clear()
+        renderComposable(root) {
+            content()
+        }
+    }
+
+    suspend fun waitChanges() {
+        waitForChanges(root)
+    }
+}
+
+internal fun runTest(block: suspend TestScope.() -> Unit): dynamic {
+    val scope = TestScope()
+    return scope.promise { block(scope) }
+}
+
+internal fun runBlockingTest(
+    block: suspend CoroutineScope.() -> Unit
+): dynamic = testScope.promise { this.block() }
+
+internal fun String.asHtmlElement() = document.createElement(this) as HTMLElement
+
+/* Currently, the recompositionRunner relies on AnimationFrame to run the recomposition and
+applyChanges. Therefore we can use this method after updating the state and before making
+assertions.
+
+If tests get broken, then DefaultMonotonicFrameClock need to be checked if it still
+uses window.requestAnimationFrame */
+internal suspend fun waitForAnimationFrame() {
+    suspendCoroutine<Unit> { continuation ->
+        window.requestAnimationFrame {
+            continuation.resume(Unit)
+        }
+    }
+}
+
+private object MutationObserverOptions : MutationObserverInit {
+    override var childList: Boolean? = true
+    override var attributes: Boolean? = true
+    override var characterData: Boolean? = true
+    override var subtree: Boolean? = true
+    override var attributeOldValue: Boolean? = true
+}
+
+internal suspend fun waitForChanges(elementId: String) {
+    waitForChanges(document.getElementById(elementId) as HTMLElement)
+}
+
+internal suspend fun waitForChanges(element: HTMLElement) {
+    suspendCoroutine<Unit> { continuation ->
+        val observer = MutationObserver { mutations, observer ->
+            continuation.resume(Unit)
+            observer.disconnect()
+        }
+        observer.observe(element, MutationObserverOptions)
+    }
+}

web/core/src/jsTest/kotlin/commonApi/ModifierTests.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import androidx.compose.web.renderComposable
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.foundation.layout.Box
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.background
+import org.jetbrains.compose.common.ui.size
+import org.jetbrains.compose.common.ui.unit.dp
+import org.w3c.dom.HTMLElement
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class ModifierTests {
+    @Test
+    fun backgroundModifier() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Box(
+                Modifier.background(Color(255, 0, 0))
+            ) { }
+        }
+
+        val el = root.firstChild
+        assertTrue(el is HTMLElement, "element not found")
+
+        assertEquals("background-color: rgb(255, 0, 0);", el.style.cssText)
+    }
+
+    @Test
+    fun size() {
+        val root = "div".asHtmlElement()
+        renderComposable(
+            root = root
+        ) {
+            Box(
+                Modifier.size(40.dp)
+            ) { }
+        }
+
+        val el = root.firstChild
+        assertTrue(el is HTMLElement, "element not found")
+
+        assertEquals("width: 40px; height: 40px;", el.style.cssText)
+    }
+}

web/core/src/jsTest/kotlin/elements/AttributesTests.kt

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package elements
+
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.setValue
+import androidx.compose.web.attributes.disabled
+import androidx.compose.web.attributes.forId
+import androidx.compose.web.elements.Button
+import androidx.compose.web.elements.Label
+import androidx.compose.web.elements.Text
+import org.w3c.dom.HTMLButtonElement
+import runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class AttributesTests {
+
+    @Test
+    fun labelForIdAttrAppliedProperly() = runTest {
+
+        composition {
+            Label(forId = "l1") { Text("label") }
+        }
+
+        assertEquals(
+            expected = "<label for=\"l1\" style=\"\">label</label>",
+            actual = root.innerHTML
+        )
+    }
+
+    @Test
+    fun labelForIdIsOptional() = runTest {
+
+        composition {
+            Label { Text("label") }
+        }
+
+        assertEquals(
+            expected = "<label style=\"\">label</label>",
+            actual = root.innerHTML
+        )
+    }
+
+    @Test
+    fun labelForIdIsAppliedFromAttrs() = runTest {
+
+        composition {
+            Label(
+                attrs = {
+                    forId("lb1")
+                }
+            ) {
+                Text("label")
+            }
+        }
+
+        assertEquals(
+            expected = "<label for=\"lb1\" style=\"\">label</label>",
+            actual = root.innerHTML
+        )
+    }
+
+    @Test
+    fun buttonDisabledAttributeAddedOnlyWhenTrue() = runTest {
+        var disabled by mutableStateOf(false)
+
+        composition {
+            Button(
+                attrs = {
+                    disabled(disabled)
+                }
+            ) {}
+        }
+
+        val btn = root.firstChild as HTMLButtonElement
+        assertEquals(null, btn.getAttribute("disabled"))
+
+        disabled = true
+        waitChanges()
+
+        assertEquals("", btn.getAttribute("disabled"))
+    }
+}

web/core/src/jsTest/kotlin/elements/EventTests.kt

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package elements
+
+import androidx.compose.web.attributes.InputType
+import androidx.compose.web.elements.Button
+import androidx.compose.web.elements.Input
+import androidx.compose.web.elements.TextArea
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.HTMLInputElement
+import org.w3c.dom.HTMLTextAreaElement
+import org.w3c.dom.events.Event
+import org.w3c.dom.events.InputEvent
+import org.w3c.dom.events.MouseEvent
+import runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class EventTests {
+
+    @Test
+    fun buttonClickHandled() = runTest {
+        var handeled = false
+
+        composition {
+            Button(
+                attrs = {
+                    onClick { handeled = true }
+                }
+            ) {}
+        }
+
+        assertEquals(1, root.childElementCount)
+
+        val btn = root.firstChild as HTMLElement
+        btn.dispatchEvent(MouseEvent("click"))
+
+        assertTrue(handeled)
+    }
+
+    @Test
+    fun checkboxInputHandled() = runTest {
+        var handeled = false
+
+        composition {
+            Input(
+                type = InputType.Checkbox,
+                attrs = {
+                    onCheckboxInput { handeled = true }
+                }
+            )
+        }
+
+        val checkbox = root.firstChild as HTMLInputElement
+        checkbox.dispatchEvent(Event("input"))
+
+        assertTrue(handeled)
+    }
+
+    @Test
+    fun radioButtonInputHandled() = runTest {
+        var handeled = false
+
+        composition {
+            Input(
+                type = InputType.Radio,
+                attrs = {
+                    onRadioInput { handeled = true }
+                }
+            )
+        }
+
+        val radio = root.firstChild as HTMLInputElement
+        radio.dispatchEvent(Event("input"))
+        assertEquals(false, radio.checked)
+
+        assertTrue(handeled)
+    }
+
+    @Test
+    fun textAreaInputHandled() = runTest {
+        var handeled = false
+
+        composition {
+            TextArea(
+                attrs = {
+                    onTextInput { handeled = true }
+                },
+                value = ""
+            )
+        }
+
+        val radio = root.firstChild as HTMLTextAreaElement
+        radio.dispatchEvent(InputEvent("input"))
+
+        assertEquals("", radio.value)
+
+        assertTrue(handeled)
+    }
+}

web/core/src/jsTest/kotlin/elements/TableTests.kt

@@ -0,0 +1,204 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package elements
+
+import androidx.compose.web.attributes.Scope
+import androidx.compose.web.attributes.colspan
+import androidx.compose.web.attributes.rowspan
+import androidx.compose.web.attributes.scope
+import androidx.compose.web.attributes.span
+import androidx.compose.web.elements.Caption
+import androidx.compose.web.elements.Col
+import androidx.compose.web.elements.Colgroup
+import androidx.compose.web.elements.Table
+import androidx.compose.web.elements.Tbody
+import androidx.compose.web.elements.Td
+import androidx.compose.web.elements.Text
+import androidx.compose.web.elements.Tfoot
+import androidx.compose.web.elements.Th
+import androidx.compose.web.elements.Thead
+import androidx.compose.web.elements.Tr
+import org.w3c.dom.HTMLElement
+import runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class TableTests {
+
+    @Test
+    fun colAttributes() = runTest {
+        composition {
+            Col(
+                attrs = {
+                    span(2)
+                }
+            ) { }
+        }
+
+        assertEquals(
+            expected = "2",
+            actual = (root.firstChild!! as HTMLElement).getAttribute("span")
+        )
+    }
+
+    @Test
+    fun create() = runTest {
+        composition {
+            Table {
+                Caption {
+                    Text("CaptionText")
+                }
+                Colgroup {
+                    Col { }
+                    Col { }
+                    Col { }
+                }
+                Thead {
+                    Tr {
+                        Th { }
+                        Th { }
+                        Th(
+                            attrs = {
+                                colspan(2)
+                            }
+                        ) {
+                            Text("First")
+                        }
+                    }
+                    Tr {
+                        Th { }
+                        Th { }
+                        Th(
+                            attrs = {
+                                scope(Scope.Col)
+                            }
+                        ) { Text("A") }
+                        Th(
+                            attrs = {
+                                scope(Scope.Col)
+                            }
+                        ) { Text("B") }
+                    }
+                }
+                Tbody {
+                    Tr {
+                        Th(
+                            attrs = {
+                                scope(Scope.Row)
+                                rowspan(2)
+                            }
+                        ) {
+                            Text("Rows")
+                        }
+                        Th(
+                            attrs = {
+                                scope(Scope.Row)
+                            }
+                        ) {
+                            Text("1")
+                        }
+                        Td {
+                            Text("30")
+                        }
+                        Td {
+                            Text("40")
+                        }
+                    }
+                    Tr {
+                        Th(
+                            attrs = {
+                                scope(Scope.Row)
+                            }
+                        ) {
+                            Text("2")
+                        }
+                        Td {
+                            Text("10")
+                        }
+                        Td {
+                            Text("20")
+                        }
+                    }
+                }
+                Tfoot {
+                    Tr {
+                        Th(
+                            attrs = {
+                                scope(Scope.Row)
+                            }
+                        ) {
+                            Text("Totals")
+                        }
+                        Th { }
+                        Td { Text("40") }
+                        Td { Text("60") }
+                    }
+                }
+            }
+        }
+
+        assertEquals(
+            expected = """
+            <table style="">
+                <caption style="">CaptionText</caption>
+                <colgroup style="">
+                    <col style="">
+                    <col style="">
+                    <col style="">
+                </colgroup>
+                <thead style="">
+                    <tr style="">
+                        <th style=""></th>
+                        <th style=""></th>
+                        <th colspan="2" style="">First</th>
+                    </tr>
+                    <tr style="">
+                        <th style=""></th>
+                        <th style=""></th>
+                        <th scope="col" style="">A</th>
+                        <th scope="col" style="">B</th>
+                    </tr>
+                </thead>
+                <tbody style="">
+                    <tr style="">
+                        <th scope="row" rowspan="2" style="">Rows</th>
+                        <th scope="row" style="">1</th>
+                        <td style="">30</td>
+                        <td style="">40</td>
+                    </tr>
+                    <tr style="">
+                        <th scope="row" style="">2</th>
+                        <td style="">10</td>
+                        <td style="">20</td>
+                    </tr>
+                </tbody>
+                <tfoot style="">
+                    <tr style="">
+                        <th scope="row" style="">Totals</th>
+                        <th style=""></th>
+                        <td style="">40</td>
+                        <td style="">60</td>
+                    </tr>
+                </tfoot>
+            </table>
+            """.trimIndent()
+                .replace("\n", "")
+                .replace("\\s{2,}".toRegex(), ""),
+            actual = root.innerHTML
+        )
+    }
+}

web/core/src/jvmMain/kotlin/withWeb/Alignment.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui
+
+import androidx.compose.ui.Alignment as JAlignment
+
+val Alignment.Vertical.implementation: JAlignment.Vertical
+    get() = when (this) {
+        Alignment.Top -> JAlignment.Top
+        Alignment.CenterVertically -> JAlignment.CenterVertically
+        else -> JAlignment.Bottom
+    }

web/core/src/jvmMain/kotlin/withWeb/Arrangement.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.foundation.layout
+
+import androidx.compose.foundation.layout.Arrangement as JArrangement
+
+val Arrangement.Horizontal.implementation: JArrangement.Horizontal
+    get() = when (this) {
+        Arrangement.End -> JArrangement.End
+        else -> JArrangement.Start
+    }

web/core/src/jvmMain/kotlin/withWeb/Color.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.core.graphics
+
+import androidx.compose.ui.graphics.Color as JColor
+
+val Color.implementation
+    get() = JColor(red, green, blue)

web/core/src/jvmMain/kotlin/withWeb/Modifier.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.ui
+
+import org.jetbrains.compose.common.ui.unit.Dp
+import org.jetbrains.compose.common.ui.unit.implementation
+import androidx.compose.foundation.background
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.core.graphics.implementation
+import org.jetbrains.compose.common.internal.castOrCreate
+import androidx.compose.foundation.layout.padding
+
+actual fun Modifier.background(color: Color): Modifier = castOrCreate().apply {
+    modifier = modifier.background(color.implementation)
+}
+
+actual fun Modifier.padding(all: Dp): Modifier = castOrCreate().apply {
+    modifier = modifier.padding(all.implementation)
+}
+
+val Modifier.implementation
+    get() = castOrCreate().modifier

web/core/src/jvmMain/kotlin/withWeb/internal/ActualModifier.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.internal
+
+import androidx.compose.ui.Modifier as JModifier
+import org.jetbrains.compose.common.ui.Modifier
+
+private class ModifierElement : JModifier.Element
+
+class ActualModifier : Modifier {
+    var modifier: JModifier = ModifierElement()
+}
+
+fun Modifier.castOrCreate(): ActualModifier = (this as? ActualModifier) ?: ActualModifier()

web/core/src/jvmMain/kotlin/withWeb/layouts/box.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.implementation
+import androidx.compose.runtime.Composable
+import androidx.compose.foundation.layout.Box as JBox
+
+@Composable
+internal actual fun BoxActual(modifier: Modifier, content: @Composable () -> Unit) {
+    JBox(modifier.implementation) {
+        content.invoke()
+    }
+}

web/core/src/jvmMain/kotlin/withWeb/layouts/button.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.implementation
+import androidx.compose.material.Button as JButton
+
+@Composable
+actual fun ButtonActual(
+    modifier: Modifier,
+    onClick: () -> Unit,
+    content: @Composable () -> Unit
+) {
+    JButton(onClick, modifier.implementation) {
+        content()
+    }
+}

web/core/src/jvmMain/kotlin/withWeb/layouts/column.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import androidx.compose.foundation.layout.Column as JColumn
+import org.jetbrains.compose.common.ui.implementation
+
+@Composable
+internal actual fun ColumnActual(modifier: Modifier, content: @Composable () -> Unit) {
+    JColumn(modifier = modifier.implementation) {
+        content.invoke()
+    }
+}

web/core/src/jvmMain/kotlin/withWeb/layouts/row.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.compose.common.foundation.layout
+
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.runtime.Composable
+import androidx.compose.foundation.layout.Row as JRow
+import org.jetbrains.compose.common.ui.implementation
+import org.jetbrains.compose.common.ui.implementation
+import org.jetbrains.compose.common.ui.Alignment
+
+@Composable
+internal actual fun RowActual(
+    modifier: Modifier,
+    horizontalArrangement: Arrangement.Horizontal,
+    verticalAlignment: Alignment.Vertical,
+    content: @Composable () -> Unit
+) {
+    JRow(
+        modifier.implementation,
+        horizontalArrangement.implementation,
+        verticalAlignment.implementation
+    ) {
+        content.invoke()
+    }
+}

web/core/src/jvmMain/kotlin/withWeb/layouts/shapes/shapes.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package jetbrains.compose.common.shapes
+
+import androidx.compose.ui.graphics.Shape as JShape
+import androidx.compose.foundation.shape.CircleShape as JCircleShape
+
+val Shape.implementation: JShape
+    get() = when (this) {
+        CircleShape -> JCircleShape
+        else -> throw ClassCastException("Currently supporting only circle shape")
+    }

web/core/src/jvmMain/kotlin/withWeb/layouts/slider.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import org.jetbrains.compose.common.ui.Modifier
+import androidx.compose.material.Slider as JSlider
+import org.jetbrains.compose.common.ui.implementation
+
+@Composable
+actual fun SliderActual(
+    value: Float,
+    onValueChange: (Float) -> Unit,
+    valueRange: ClosedFloatingPointRange<Float>,
+    steps: Int,
+    modifier: Modifier
+) {
+    JSlider(
+        value,
+        onValueChange = onValueChange,
+        modifier = modifier.implementation,
+        valueRange = valueRange,
+        steps = steps
+    )
+}

web/core/src/jvmMain/kotlin/withWeb/layouts/text.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.common.material
+
+import androidx.compose.runtime.Composable
+import androidx.compose.material.Text as JText
+import org.jetbrains.compose.common.ui.Modifier
+import org.jetbrains.compose.common.ui.implementation
+import org.jetbrains.compose.common.core.graphics.Color
+import org.jetbrains.compose.common.core.graphics.implementation
+import org.jetbrains.compose.common.ui.unit.TextUnit
+import org.jetbrains.compose.common.ui.unit.implementation
+
+@Composable
+actual fun TextActual(
+    text: String,
+    modifier: Modifier,
+    color: Color,
+    size: TextUnit
+) {
+    JText(
+        text,
+        modifier = modifier.implementation,
+        color = color.implementation,
+        fontSize = size.implementation
+    )
+}