feat(shell-dashboard): sticky-pin overlay toggle bar to viewport top on scroll

Author: jpr5

showcase/shell-dashboard/src/app/page.tsx

@@ -172,7 +172,7 @@ export default function Page() {
       {/* Tab content */}
       {activeTab === "matrix" && (
         <>
-          <div className="px-8 pt-4 flex flex-col gap-3">
+          <div className="sticky top-0 z-30 px-8 py-3 flex flex-col gap-3 bg-[var(--bg-surface)] border-b border-[var(--border)]">
             <OverlayToggleBar
               overlays={overlays}
               onToggle={toggle}