Update video-detail.module.less

src/student/video-class/video-detail.module.less

@@ -1,4 +1,7 @@
 .video-detail {
+  height: 100vh;
+  overflow: scroll; //主要是这个
+  box-sizing: border-box;
   .introduction {
     color: #7a7a7a;
     line-height: 23px;