Basic support for letter-spacing in CSS API

web/core/src/jsMain/kotlin/org/jetbrains/compose/web/css/properties/font.kt

@@ -42,3 +42,12 @@ fun StyleBuilder.lineHeight(value: CSSNumeric) {
 fun StyleBuilder.font(value: String) {
     property("font", value)
 }
+
+// https://developer.mozilla.org/en-US/docs/Web/CSS/letter-spacing
+fun StyleBuilder.letterSpacing(value: String) {
+    property("letter-spacing", value)
+}
+
+fun StyleBuilder.letterSpacing(value: CSSNumeric) {
+    property("letter-spacing", value)
+}

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

@@ -104,6 +104,25 @@ class CSSFontTests {
         assertEquals("2em", (root.children[1] as HTMLElement).style.lineHeight)
     }
 
+    @Test
+    fun letterSpacing() = runTest {
+        composition {
+            Div({
+                style {
+                    letterSpacing("normal")
+                }
+            })
+            Div({
+                style {
+                    letterSpacing(2.em)
+                }
+            })
+        }
+
+        assertEquals("normal", (root.children[0] as HTMLElement).style.letterSpacing)
+        assertEquals("2em", (root.children[1] as HTMLElement).style.letterSpacing)
+    }
+
     @Test
     fun fontFamily() = runTest {
         composition {