style：修改树形选择框下拉样式

src/components/drawers/AddLevelAddStu.vue

@@ -98,7 +98,7 @@
                       <a-tree-select
                         v-model:value="valueSelect"
                         style="width: 200px"
-                        dropdownClassName="dropdownn"
+                        dropdownClassName="changetreedropdown"
                         :dropdown-style="{
                           maxHeight: '400px',
                           overflow: 'auto',
@@ -1006,12 +1006,14 @@ export default {
               }
             }
           }
+
           .tab2 {
             display: flex;
             align-items: center;
             margin-top: 10px;
             flex-wrap: wrap;
             justify-content: space-between;
+
             .t1 {
               display: flex;
               align-items: center;
@@ -1022,9 +1024,9 @@ export default {
               font-size: 14px;
               white-space: nowrap;
             }
-            .dropdownn {
-              background-color: red;
-              border-radius: 10px;
+
+            .ant-select-dropdown {
+              min-width: 800px !important;
             }
             .ant-select {
               border-radius: 8px !important;
@@ -1202,4 +1204,14 @@ export default {
     }
   }
 }
+.changetreedropdown {
+  width: 550px !important;
+}
+
+.ant-select-tree-list-scrollbar {
+  width: 5px !important;
+  .ant-select-tree-list-scrollbar-thumb {
+    background-color: #4ea6ff !important;
+  }
+}
 </style>