feat: Applied glassmorphism styling (backdrop-filter blur, semi-transpa…

- "src/frontend/src/pages/ChannelDetail.tsx"

GSD-Task: S03/T03

src/frontend/src/pages/ChannelDetail.tsx

@@ -1304,7 +1304,7 @@ export function ChannelDetail() {
         ) : null}
       </div>
 
-      {/* Floating bulk action bar */}
+      {/* Floating bulk action bar — glassmorphism */}
       {selectedIds.size > 0 ? (
         <div
           role="toolbar"
@@ -1319,10 +1319,12 @@ export function ChannelDetail() {
             alignItems: 'center',
             gap: 'var(--space-3)',
             padding: 'var(--space-3) var(--space-5)',
-            backgroundColor: 'var(--bg-card)',
-            border: '1px solid var(--border)',
+            backgroundColor: 'rgba(30, 32, 40, 0.75)',
+            backdropFilter: 'blur(16px) saturate(1.4)',
+            WebkitBackdropFilter: 'blur(16px) saturate(1.4)',
+            border: '1px solid rgba(255, 255, 255, 0.08)',
             borderRadius: 'var(--radius-xl)',
-            boxShadow: 'var(--shadow-lg)',
+            boxShadow: '0 8px 32px rgba(0, 0, 0, 0.35), inset 0 0.5px 0 rgba(255, 255, 255, 0.06)',
           }}
         >
           <span