Pick decks. Cards are mixed across decks so topic never gives the answer away.
One phone is the host. Host reads the prompt, everyone answers out loud, host grades. Nothing to tap through, nothing to eliminate.
Decks are plain JSON in decks/. Edit or add your own; list them in decks/index.json.
Progress lives in this browser. A sync link carries it to another device and merges the two; nothing is sent to a server.