perf: 完善黑夜模式的表现效果，工作流编排幕布和节点在黑夜模式正常表现

easyflow-ui-admin/packages/tinyflow-ui/src/components/TinyflowCore.svelte

@@ -461,17 +461,18 @@
 <style>
     .panel-content {
         padding: 10px;
-        background-color: #fff;
+        background-color: var(--tf-bg-surface);
         border-radius: 5px;
-        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
+        box-shadow: var(--tf-shadow-soft);
         width: 200px;
-        border: 1px solid #efefef;
+        border: 1px solid var(--tf-border-color);
+        color: var(--tf-text-primary);
     }
 
     .setting-title {
         margin: 10px 0;
         font-size: 12px;
-        color: #999;
+        color: var(--tf-text-muted);
     }
 
     .setting-item {
@@ -487,13 +488,13 @@
 
     .readonly-edge-branch {
         font-size: 12px;
-        color: #6b7280;
+        color: var(--tf-text-secondary);
         margin-bottom: 8px;
     }
 
     .readonly-edge-tip {
         margin-top: 6px;
         font-size: 12px;
-        color: #9ca3af;
+        color: var(--tf-text-muted);
     }
 </style>