fix UI.

src/admin/problem/detail.vue

@@ -423,7 +423,8 @@ watch([fromExistingTags, newTags], (tags) => {
     </n-form-item>
   </n-form>
   <n-tabs
-    type="segment"
+    type="line"
+    default-value="C"
     class="template box"
     v-if="needTemplate"
     v-model:value="currentActiveTemplate"