docs: improve style (#12024)

packages/vant/src/button/demo/index.vue

@@ -189,9 +189,10 @@ const t = useTranslate({
   &-row {
     margin-bottom: var(--van-padding-sm);
   }
-}
+
   .notice-swipe {
     height: 40px;
     line-height: 40px;
   }
+}
 </style>

packages/vant/src/rolling-text/demo/index.vue

@@ -148,6 +148,7 @@ const reset = () => {
 </template>
 
 <style lang="less">
+.demo-rolling-text {
   .van-button {
     margin-left: var(--van-padding-md);
   }
@@ -156,10 +157,6 @@ const reset = () => {
     margin-left: var(--van-padding-md);
   }
 
-.van-grid {
-  margin-left: var(--van-padding-md);
-}
-
   .my-rolling-text {
     --van-rolling-text-background: #1989fa;
     --van-rolling-text-color: white;
@@ -168,4 +165,5 @@ const reset = () => {
     --van-rolling-text-item-border-radius: 5px;
     --van-rolling-text-item-width: 40px;
   }
+}
 </style>