Introduce minimal backgroundAttachment to the CSS API

web/core/src/jsMain/kotlin/androidx/compose/web/css/properties/background.kt

@@ -12,3 +12,8 @@ fun StyleBuilder.backgroundColor(value: String) {
 fun StyleBuilder.backgroundColor(value: CSSColorValue) {
     property("background-color", value)
 }
+
+// https://developer.mozilla.org/en-US/docs/Web/CSS/background-attachment
+fun StyleBuilder.backgroundAttachment(value: String) {
+    property("background-attachment", value)
+}

web/core/src/jsTest/kotlin/css/CSSBackgroundTests.kt

@@ -7,6 +7,7 @@ package org.jetbrains.compose.web.core.tests.css
 
 import kotlinx.browser.window
 import org.jetbrains.compose.web.core.tests.runTest
+import org.jetbrains.compose.web.css.backgroundAttachment
 import org.jetbrains.compose.web.css.backgroundColor
 import org.jetbrains.compose.web.dom.Div
 import org.w3c.dom.HTMLElement
@@ -29,4 +30,24 @@ class CSSBackgroundTests {
         assertEquals("rgb(0, 128, 0)", window.getComputedStyle(root.children[0] as HTMLElement).backgroundColor)
         assertEquals("rgba(0, 129, 0, 0.2)", window.getComputedStyle(root.children[1] as HTMLElement).backgroundColor)
     }
+
+    @Test
+    fun backgroundAttachment() = runTest {
+        composition {
+            Div({style {
+                backgroundAttachment("scroll")
+            }})
+            Div({style {
+                backgroundAttachment("fixed")
+            }})
+            Div({style {
+                backgroundAttachment("local")
+            }})
+        }
+
+        assertEquals("scroll", window.getComputedStyle(root.children[0] as HTMLElement).backgroundAttachment)
+        assertEquals("fixed", window.getComputedStyle(root.children[1] as HTMLElement).backgroundAttachment)
+        assertEquals("local", window.getComputedStyle(root.children[2] as HTMLElement).backgroundAttachment)
+    }
+
 }