Merge branch 'Leaderboard-8.30' into dev

src/student/leaderboard/index.module.less

@@ -100,6 +100,7 @@
   width: 100%;
   box-sizing: border-box;
   box-shadow: 0 -8px 12px #ebedf0;
+  background-color: #fff;
   :global {
     .van-cell__value {
       flex: initial;

src/student/share-active/track-review-activity/index.tsx

@@ -81,6 +81,13 @@ export default defineComponent({
     // 判断活动状态的活动时间
     this.checkActivityTime()
   },
+  unmounted() {
+    const visibilityChangeEvent = this.hiddenProperty.replace(
+      /hidden/i,
+      'visibilitychange'
+    )
+    document.removeEventListener(visibilityChangeEvent, this.onVisibilityChange)
+  },
   methods: {
     onVisibilityChange() {
       if (!document[this.hiddenProperty]) {