You're viewing the static file — the styled prototype runs on the dev server.

The Zone design system is compiled live by Vite, so a static file can't render it. Point this preview at the dev server instead:

1. Open the source dropdown at the panel's top-left (the globe / chevron next to the filename).
2. Choose prototype-kit — http://localhost:5173. It sticks for the whole session.

Or open it directly in your browser:
http://localhost:5173/