chore: 题库选择UI微调

src/pages/learn/selectCategory.vue

@@ -200,13 +200,12 @@ export default {
       color: transparent;
       display: none;
     }
-    padding-bottom: 24rpx;
     height: 100%;
     overflow: auto;
     position: relative;
 
     .label-list {
-      margin-bottom: 20rpx;
+      margin-bottom: 44rpx;
       .label-list-content {
         margin: 0 24rpx;
       }