feat(Card): add variant prop

playground/app/pages/components/card.vue

@@ -1,6 +1,16 @@
+<script setup lang="ts">
+import theme from '#build/ui/card'
+
+const variants = Object.keys(theme.variants.variant)
+
+const variant = ref(theme.defaultVariants.variant)
+</script>
+
 <template>
   <div class="flex flex-col gap-4">
-    <UCard class="w-96">
+    <USelect v-model="variant" :items="variants" />
+
+    <UCard :variant="variant" class="w-96">
       <template #header>
         <Placeholder class="h-8" />
       </template>