加宽左侧导航栏 - 从280px增加到320px，优化内边距和间距

demo/frontend/src/views/Home.vue

@@ -291,7 +291,7 @@ onMounted(() => {
 
 /* 左侧导航栏 */
 .sidebar {
-  width: 280px;
+  width: 320px;
   background: white;
   border-right: 1px solid #e2e8f0;
   display: flex;
@@ -302,7 +302,7 @@ onMounted(() => {
 .logo {
   display: flex;
   align-items: center;
-  padding: 0 24px;
+  padding: 0 28px;
   margin-bottom: 32px;
 }
 
@@ -322,13 +322,13 @@ onMounted(() => {
 
 .nav-menu {
   flex: 1;
-  padding: 0 16px;
+  padding: 0 20px;
 }
 
 .nav-item {
   display: flex;
   align-items: center;
-  padding: 12px 16px;
+  padding: 14px 20px;
   margin-bottom: 4px;
   border-radius: 8px;
   cursor: pointer;
@@ -357,7 +357,7 @@ onMounted(() => {
 }
 
 .sidebar-footer {
-  padding: 0 24px;
+  padding: 0 28px;
   margin-top: auto;
 }