优化 整体风格统一化调整

src/App.tsx

@@ -54,21 +54,23 @@ function AppContent() {
 
   return (
     <div className="h-screen bg-gray-50 text-gray-900 flex flex-col font-sans">
-      <div className="shadow-sm">
+      <div className="card card-lg rounded-none">
         <Header />
       </div>
       
-      <div className="flex-1 flex overflow-hidden">
+      <div className="flex-1 flex overflow-hidden p-4 gap-4">
         <div className={cn("flex-shrink-0 transition-all duration-300", !showPromptPanel && "w-8")}>
-          <div className="h-full shadow-lg">
+          <div className="h-full card card-lg">
             <PromptComposer />
           </div>
         </div>
         <div className="flex-1 min-w-0">
-          <ImageCanvas />
+          <div className="h-full card card-lg">
+            <ImageCanvas />
+          </div>
         </div>
         <div className="flex-shrink-0">
-          <div className="h-full shadow-lg">
+          <div className="h-full card card-lg">
             <HistoryPanel />
           </div>
         </div>