now project is multiplatform and correctly working

src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitButton.kt

@@ -0,0 +1,14 @@
+package dev.inmo.jsuikit.modifiers
+
+sealed class UIKitButton(suffix: String) : UIKitModifier {
+    override val classes: Array<String> = arrayOf("uk-button-$suffix")
+
+    sealed class Type(suffix: String) : UIKitButton(suffix) {
+        object Default : Type("default")
+        object Primary : Type("primary")
+        object Secondary : Type("secondary")
+        object Danger : Type("danger")
+        object Text : Type("text")
+        object Link : Type("link")
+    }
+}