diff --git a/colorpicker/api/colorpicker.klib.api b/colorpicker/api/colorpicker.klib.api
index 50412299..836e9274 100644
--- a/colorpicker/api/colorpicker.klib.api
+++ b/colorpicker/api/colorpicker.klib.api
@@ -1,5 +1,5 @@
 // Klib ABI Dump
-// Targets: [iosArm64, iosSimulatorArm64]
+// Targets: [iosArm64, iosSimulatorArm64, wasmJs]
 // Rendering settings:
 // - Signature version: 2
 // - Show manifest properties: true
diff --git a/colorpicker/build.gradle.kts b/colorpicker/build.gradle.kts
index 240e3e97..10c9adda 100644
--- a/colorpicker/build.gradle.kts
+++ b/colorpicker/build.gradle.kts
@@ -1,6 +1,7 @@
 import com.vanniktech.maven.publish.JavadocJar
 import com.vanniktech.maven.publish.KotlinMultiplatform
 import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
+import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 plugins {
@@ -18,6 +19,18 @@ version = providers.gradleProperty("VERSION_NAME").get()
 kotlin {
     explicitApi()
 
+    // Compose Multiplatform for web. The DSL is still marked experimental in the Kotlin
+    // Gradle plugin, so the opt-in is required and the shape may change between Kotlin
+    // versions; the library itself needs no wasm-specific source.
+    @OptIn(ExperimentalWasmDsl::class)
+    wasmJs {
+        browser()
+        // Required even for a library: without an executable binary webpack does not
+        // bundle the Skiko runtime, and the browser test target cannot load Compose.
+        // See https://youtrack.jetbrains.com/issue/CMP-4906
+        binaries.executable()
+    }
+
     jvm()
 
     android {
diff --git a/colorpicker/src/commonTest/kotlin/codes/side/colorpicker/ui/HueFractionMappingTest.kt b/colorpicker/src/commonTest/kotlin/codes/side/colorpicker/ui/HueFractionMappingTest.kt
index 5d719fb7..a7f655da 100644
--- a/colorpicker/src/commonTest/kotlin/codes/side/colorpicker/ui/HueFractionMappingTest.kt
+++ b/colorpicker/src/commonTest/kotlin/codes/side/colorpicker/ui/HueFractionMappingTest.kt
@@ -1,7 +1,6 @@
 package codes.side.colorpicker.ui
 
 import codes.side.colorpicker.state.ColorPickerState
-import kotlin.math.nextDown
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
@@ -11,6 +10,11 @@ import kotlin.test.assertTrue
  * the equivalent 0, so the slider must never write exactly 360 — otherwise dragging
  * the thumb to the right end of the track would snap it back to the far left.
  */
+// kotlin.math.nextDown is unavailable on wasmJs, and this test runs in commonTest, so it
+// compiles for every target. Computed here from the bit pattern rather than reusing the
+// implementation's own constant, which would make these assertions circular.
+private val JUST_BELOW_360 = Float.fromBits(360f.toRawBits() - 1)
+
 class HueFractionMappingTest {
 
     @Test
@@ -27,7 +31,7 @@ class HueFractionMappingTest {
     fun fullFractionMapsJustBelow360() {
         val hue = hueFromFraction(1f)
         assertTrue(hue < 360f, "hue at the track end must stay below 360, was $hue")
-        assertEquals(360f.nextDown(), hue)
+        assertEquals(JUST_BELOW_360, hue)
     }
 
     @Test
@@ -36,7 +40,7 @@ class HueFractionMappingTest {
         // hue must read back unchanged instead of wrapping to 0.
         val state = ColorPickerState()
         state.updateHue(hueFromFraction(1f))
-        assertEquals(360f.nextDown(), state.hslColor.hue)
+        assertEquals(JUST_BELOW_360, state.hslColor.hue)
     }
 
     @Test
@@ -58,6 +62,6 @@ class HueFractionMappingTest {
         state.updateHue(hueFromFraction(1f))
         val redisplayedFraction = state.hslColor.hue / 360f
         state.updateHue(hueFromFraction(redisplayedFraction))
-        assertEquals(360f.nextDown(), state.hslColor.hue)
+        assertEquals(JUST_BELOW_360, state.hslColor.hue)
     }
 }
diff --git a/kotlin-js-store/wasm/yarn.lock b/kotlin-js-store/wasm/yarn.lock
new file mode 100644
index 00000000..62b6bd5f
--- /dev/null
+++ b/kotlin-js-store/wasm/yarn.lock
@@ -0,0 +1,8 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+"@js-joda/core@3.2.0":
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/@js-joda/core/-/core-3.2.0.tgz#3e61e21b7b2b8a6be746df1335cf91d70db2a273"
+  integrity sha512-PMqgJ0sw5B7FKb2d5bWYIoxjri+QlW/Pys7+Rw82jSH0QN3rB05jZ/VrrsUdh1w4+i2kw9JOejXGq/KhDOX7Kg==