feat: 添加暗色主题支持

- 在HTML根元素添加dark类名以启用暗色模式
- 引入Element Plus暗色主题CSS变量文件
- 格式化代码缩进和结构，提升代码可读性

Yi.Bbs.Vue3/src/main.js

@@ -8,7 +8,7 @@ import piniaPluginPersistedstate from "pinia-plugin-persistedstate";
 import "element-plus/dist/index.css";
 import "./assets/main.css";
 import "@/assets/styles/index.scss"; // global css
-
+import 'element-plus/theme-chalk/dark/css-vars.css'
 
 import * as ElementPlusIconsVue from "@element-plus/icons-vue";
 import directive from "./directive"; // directive
@@ -16,17 +16,17 @@ import VueLuckyCanvas from '@lucky-canvas/vue'
 
 import "./permission";
 
-(async () => {
-  const app = createApp(App);
-  for (const [key, component] of Object.entries(ElementPlusIconsVue)) {
-    app.component(key, component);
-  }
-  const pinia = createPinia();
-  pinia.use(piniaPluginPersistedstate);
-  app.use(pinia);
-  directive(app);
-  app.use(router);
-  app.use(VueLuckyCanvas);
-  await router.isReady();
-  app.mount("#app");
-})();
+(async() => {
+    const app = createApp(App);
+    for (const [key, component] of Object.entries(ElementPlusIconsVue)) {
+        app.component(key, component);
+    }
+    const pinia = createPinia();
+    pinia.use(piniaPluginPersistedstate);
+    app.use(pinia);
+    directive(app);
+    app.use(router);
+    app.use(VueLuckyCanvas);
+    await router.isReady();
+    app.mount("#app");
+})();