Revert "fix: [공통] 하단 고정 액션바 시각적 구분 강화"

This reverts commit 954cddfd1e94ec13dfb64e5fbcd0cfd27f619635.

src/components/templates/IntegratedDetailTemplate/components/DetailActions.tsx

@@ -110,7 +110,7 @@ export function DetailActions({
   // 모바일: 좌우 여백 16px (left-4 right-4)
   // 태블릿/데스크탑: 사이드바 펼침(w-64=256px), 접힘(w-24=96px) + 콘텐츠 패딩(24px) 맞춤
   const stickyStyles = sticky
-    ? `fixed bottom-4 left-4 right-4 px-4 py-3 bg-background border-t-4 border-t-primary/20 border rounded-xl shadow-lg z-50 transition-all duration-300 md:bottom-6 md:px-6 md:right-[24px] ${sidebarCollapsed ? 'md:left-[120px]' : 'md:left-[280px]'}`
+    ? `fixed bottom-4 left-4 right-4 px-4 py-3 bg-background/95 backdrop-blur rounded-xl border shadow-lg z-50 transition-all duration-300 md:bottom-6 md:px-6 md:right-[24px] ${sidebarCollapsed ? 'md:left-[120px]' : 'md:left-[280px]'}`
     : '';
 
   // 공통 레이아웃: 왼쪽(뒤로) | 오른쪽(액션들)