fix(layout): 修复侧边栏嵌套子菜单折叠指示箭头错位问题

shierfeng-fastapi-frontend/src/assets/styles/sidebar.scss

@@ -98,6 +98,16 @@
       display: inline-block !important;
     }
 
+    .el-sub-menu {
+      .el-sub-menu__icon-arrow {
+        position: absolute;
+        top: 50%;
+        right: var(--el-menu-base-level-padding, 20px);
+        margin-top: -6px;
+        width: auto !important;
+      }
+    }
+
     // menu hover
     .sub-menu-title-noDropdown,
     .el-sub-menu__title {
@@ -126,6 +136,14 @@
       &:hover {
         background-color: rgba(0, 0, 0, 0.06) !important;
       }
+
+      .el-sub-menu__icon-arrow {
+        position: absolute;
+        top: 50%;
+        right: var(--el-menu-base-level-padding, 20px);
+        margin-top: -6px;
+        width: auto !important;
+      }
     }
 
     & .theme-dark .nest-menu .el-sub-menu>.el-sub-menu__title,
@@ -235,6 +253,16 @@
 
 // when menu collapsed
 .el-menu--vertical {
+  .el-sub-menu {
+    .el-sub-menu__icon-arrow {
+      position: absolute;
+      top: 50%;
+      right: var(--el-menu-base-level-padding, 20px);
+      margin-top: -6px;
+      width: auto !important;
+    }
+  }
+
   &>.el-menu {
     .svg-icon {
       margin-right: 16px;