style: 颜色统一为CSS变量并优化复习卡片交互

src/main.ts

@@ -1,11 +1,12 @@
-import './assets/main.css'
-
 import { createApp } from 'vue'
 import ElementPlus from 'element-plus'
 import 'element-plus/dist/index.css'
+import 'normalize.css'
+// 必须在 EP 样式之后：同特异度下靠加载顺序覆盖 EP 主题变量
+import './assets/main.css'
+
 import App from './App.vue'
 import router from "@/router"
-import 'normalize.css'
 
 const app = createApp(App)
 app.use(ElementPlus)