test(example): add test case

packages/playground/css/index.vue

@@ -1,5 +1,10 @@
 <template>
-  <div class="css-in-less">test for import css in less with SFC</div>
+  <div class="css-in-less">
+    test for import css in less with SFC, color will be yellow
+  </div>
+  <div class="css-in-less-2">
+    test for import less in less with SFC, color will be blue
+  </div>
 </template>
 
 <script setup></script>

packages/playground/css/nested/css-in-less.less

@@ -1 +1,5 @@
+@import url('./css-in-less.css');
 @import './css-in-less.css';
+
+@import url('./css-in-less-2.less');
+@import './css-in-less-2.less';