Keep the stalls side by side on wide screens and stacked on a phone.
The preceding demo showed the same technique on different cards. The HTML supplies the cards; edit style.css for the requested change.
@media (max-width: 36rem) to make .responsive-grid one column on narrow screens.Run Preview to see the change, then Submit.
Use the demo as a reference, but write the rules yourself.
Run Preview before Submit to inspect the visible result.