[breaking change] rebuild style struct (#2021)

packages/circle/demo/index.vue

@@ -61,7 +61,7 @@ export default {
 };
 </script>
 
-<style lang="postcss">
+<style lang="less">
 .demo-circle {
   .van-circle {
     margin-left: 15px;

packages/circle/index.less

@@ -0,0 +1,33 @@
+@import '../style/var';
+
+.van-circle {
+  position: relative;
+  text-align: center;
+  display: inline-block;
+
+  svg {
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    position: absolute;
+  }
+
+  &__layer {
+    fill: none;
+    stroke-linecap: round;
+    stroke-dasharray: 3140;
+    stroke-dashoffset: 3140;
+    transform: rotate(90deg);
+    transform-origin: center;
+  }
+
+  &__text {
+    top: 50%;
+    left: 0;
+    width: 100%;
+    color: @text-color;
+    position: absolute;
+    transform: translateY(-50%);
+  }
+}