perf[Style]: optimize the sidebar style to make it better to set

src/styles/sidebar.scss

 #app {
 
-  // 主体区域
+  // 主体区域 Main container
   .main-container {
     min-height: 100%;
     transition: margin-left .28s;
@@ -8,7 +8,7 @@
     position: relative;
   }
 
-  // 侧边栏
+  // 侧边栏 Sidebar container
   .sidebar-container {
     transition: width 0.28s;
     width: $sideBarWidth !important;
@@ -26,10 +26,6 @@
       transition: 0s width ease-in-out, 0s padding-left ease-in-out, 0s padding-right ease-in-out;
     }
 
-    .el-scrollbar__bar.is-vertical {
-      right: 0px;
-    }
-
     .scrollbar-wrapper {
       overflow-x: hidden !important;
 
@@ -38,6 +34,10 @@
       }
     }
 
+    .el-scrollbar__bar.is-vertical {
+      right: 0px;
+    }
+
     .is-horizontal {
       display: none;
     }
@@ -58,8 +58,26 @@
       width: 100% !important;
     }
 
+    // menu hover
+    .submenu-title-noDropdown,
+    .el-submenu__title {
+      &:hover {
+        background-color: $menuHover !important;
+      }
+    }
+
     .is-active>.el-submenu__title {
-      color: #f4f4f5 !important;
+      color: $subMenuActiveText !important;
+    }
+
+    & .nest-menu .el-submenu>.el-submenu__title,
+    & .el-submenu .el-menu-item {
+      min-width: $sideBarWidth !important;
+      background-color: $subMenuBg !important;
+
+      &:hover {
+        background-color: $subMenuHover !important;
+      }
     }
   }
 
@@ -108,21 +126,11 @@
     }
   }
 
-  .sidebar-container .nest-menu .el-submenu>.el-submenu__title,
-  .sidebar-container .el-submenu .el-menu-item {
-    min-width: $sideBarWidth !important;
-    background-color: $subMenuBg !important;
-
-    &:hover {
-      background-color: $menuHover !important;
-    }
-  }
-
   .el-menu--collapse .el-menu .el-submenu {
     min-width: $sideBarWidth !important;
   }
 
-  //适配移动端
+  // 适配移动端, Mobile responsive
   .mobile {
     .main-container {
       margin-left: 0px;
@@ -135,6 +143,7 @@
 
     &.hideSidebar {
       .sidebar-container {
+        pointer-events: none;
         transition-duration: 0.3s;
         transform: translate3d(-$sideBarWidth, 0, 0);
       }
@@ -150,10 +159,19 @@
   }
 }
 
+// when menu collapsed
 .el-menu--vertical {
   &>.el-menu {
     .svg-icon {
       margin-right: 16px;
     }
   }
+
+  .nest-menu .el-submenu>.el-submenu__title,
+  .el-menu-item {
+    &:hover {
+      // You can use $subMenuHover
+      background-color: $menuHover !important;
+    }
+  }
 }

src/styles/variables.scss

 //sidebar
+$menuText:#bfcbd9;
+$menuActiveText:#409EFF;
+$subMenuActiveText:#f4f4f5; //https://github.com/ElemeFE/element/issues/12951
+
 $menuBg:#304156;
+$menuHover:#263445;
+
 $subMenuBg:#1f2d3d;
-$menuHover:#001528;
+$subMenuHover:#001528;
+
 $sideBarWidth: 180px;
+
+// the :export directive is the magic sauce for webpack
+:export {
+  menuText: $menuText;
+  menuActiveText: $menuActiveText;
+  subMenuActiveText: $subMenuActiveText;
+  menuBg: $menuBg;
+  menuHover: $menuHover;
+  subMenuBg: $subMenuBg;
+  subMenuHover: $subMenuHover;
+  sideBarWidth: $sideBarWidth;
+}

src/views/layout/components/Sidebar/index.vue

@@ -4,10 +4,10 @@
       :show-timeout="200"
       :default-active="$route.path"
       :collapse="isCollapse"
+      :background-color="variables.menuBg"
+      :text-color="variables.menuText"
+      :active-text-color="variables.menuActiveText"
       mode="vertical"
-      background-color="#304156"
-      text-color="#bfcbd9"
-      active-text-color="#409EFF"
     >
       <sidebar-item v-for="route in routes" :key="route.path" :item="route" :base-path="route.path"/>
     </el-menu>
@@ -16,6 +16,7 @@
 
 <script>
 import { mapGetters } from 'vuex'
+import variables from '@/styles/variables.scss'
 import SidebarItem from './SidebarItem'
 
 export default {
@@ -27,6 +28,9 @@ export default {
     routes() {
       return this.$router.options.routes
     },
+    variables() {
+      return variables
+    },
     isCollapse() {
       return !this.sidebar.opened
     }