Update Barcode Label Management Page UI for Consistency

- Changed background color of the main container from white to card style for better visual consistency with the overall design.
- Updated the CardHeader background to a muted style, enhancing the aesthetic appeal and aligning with the new design guidelines.

These changes improve the user interface of the Barcode Label Management page, ensuring a cohesive look and feel across the application.

frontend/app/(main)/admin/screenMng/barcodeList/page.tsx

@@ -34,7 +34,7 @@ export default function BarcodeLabelManagementPage() {
   return (
     <div className="min-h-screen bg-muted">
       <div className="w-full max-w-none space-y-8 px-4 py-8">
-        <div className="flex items-center justify-between rounded-lg border bg-white p-6 shadow-sm">
+        <div className="flex items-center justify-between rounded-lg border bg-card p-6 shadow-sm">
           <div>
             <h1 className="text-3xl font-bold text-foreground">바코드 라벨 관리</h1>
             <p className="mt-2 text-muted-foreground">ZD421 등 바코드 프린터용 라벨을 작성하고 출력합니다</p>
@@ -79,7 +79,7 @@ export default function BarcodeLabelManagementPage() {
 
         {/* 카메라 스캔: 바코드 값을 텍스트로 추출해 표시 */}
         <Card className="shadow-sm">
-          <CardHeader className="bg-gray-50/50">
+          <CardHeader className="bg-muted/50">
             <CardTitle className="flex items-center gap-2">
               <Scan className="h-5 w-5" />
               바코드 스캔