侧边导航背景色改为 #282828

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/frontend/src/App.vue

@@ -24,7 +24,7 @@ function logout() {
       <el-menu
         :default-active="route.path"
         router
-        background-color="#1f2d3d"
+        background-color="#282828"
         text-color="#cfd8e3"
         active-text-color="#ffffff"
       >
@@ -76,7 +76,7 @@ body {
   height: 100%;
 }
 .aside {
-  background: #1f2d3d;
+  background: #282828;
   color: #cfd8e3;
 }
 .brand {
@@ -86,7 +86,7 @@ body {
   justify-content: center;
   font-size: 18px;
   letter-spacing: 2px;
-  border-bottom: 1px solid #344558;
+  border-bottom: 1px solid #3a3a3a;
 }
 .header {
   display: flex;