fix: 顶部标题栏加暗色背景——白色文字在暗底上清晰显示

frontend/src/view/dashboard/index.vue

@@ -137,7 +137,9 @@ onUnmounted(() => {
 /* === Bar === */
 .monitor-bar {
   display: flex; justify-content: space-between; align-items: center;
-  padding-bottom: 20px; border-bottom: 1px solid #1e3240; margin-bottom: 28px;
+  padding: 16px 20px; margin: -24px -32px 28px;
+  background: var(--panel);
+  border-bottom: 1px solid #1e3240;
 }
 .bar-left { display: flex; align-items: center; gap: 10px; }
 .bar-dot {