Give the shell one header, a skip link, and a cookie-aware first paint.

Breakpoint clones were still in the tab order, marketing always painted Log in, and at 430px the logo overlay covered Use cases and Learn.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/(marketing-case-study)/layout.tsx

@@ -1,6 +1,7 @@
 import type { ReactNode } from "react";
 import { MessagesProvider } from "../contexts/MessagesContext";
 import { AuthModalProvider } from "../contexts/AuthModalContext";
+import { MAIN_CONTENT_ID } from "../../lib/mainContent";
 import marketingMessages from "../../messages/en/marketing";
 
 /** Full-viewport case-study surfaces (completed rule demos) — no marketing footer. */
@@ -12,7 +13,11 @@ export default function MarketingCaseStudyLayout({
   return (
     <MessagesProvider messages={marketingMessages}>
       <AuthModalProvider>
-        <main className="flex h-dvh min-h-0 flex-col overflow-hidden">
+        <main
+          id={MAIN_CONTENT_ID}
+          tabIndex={-1}
+          className="flex h-dvh min-h-0 flex-col overflow-hidden outline-none"
+        >
           {children}
         </main>
       </AuthModalProvider>