fix routes.

src/shared/layout/admin.vue

@@ -8,6 +8,10 @@ const route = useRoute()
 const router = useRouter()
 const userStore = useUserStore()
 const options: MenuOption[] = [
+  {
+    label: () => h(RouterLink, { to: "/" }, { default: () => "返回 OJ" }),
+    key: "return to OJ",
+  },
   {
     label: () => h(RouterLink, { to: "/admin" }, { default: () => "首页" }),
     key: "admin home",
@@ -101,19 +105,14 @@ onMounted(async () => {
 </script>
 
 <template>
-  <div class="admin">
-    <n-layout-sider width="160" bordered>
+  <n-layout has-sider position="absolute">
+    <n-layout-sider width="160" bordered :native-scrollbar="false">
       <n-menu :options="options" :value="active" />
     </n-layout-sider>
     <n-layout-content content-style="padding: 16px; min-width: 600px">
       <router-view></router-view>
     </n-layout-content>
-  </div>
+  </n-layout>
 </template>
 
-<style scoped>
-.admin {
-  margin: -16px;
-  display: flex;
-}
-</style>
+<style scoped></style>