fix: 修改UI结构，封装切换按钮

src/styles/common/theme.scss

@@ -0,0 +1,10 @@
+@import './mixins/config.scss';
+@import './_dark.scss';
+@import './_light.scss';
+
+$themes: (
+  // 亮白
+  #{$theme-light}: $light,
+  // 暗黑
+  #{$theme-dark}: $dark
+);