I need a lightweight proof-of-concept that lets a Teacher push a single chess puzzle to every Student in real time and then watch, from a simple dashboard, who has already solved it. Only two user types are involved—Teacher and Student—and students must see nothing except the puzzle itself once they enter their PIN, effectively putting the device in kiosk-style locked mode. Core flow • Teacher logs in, selects one puzzle, and presses “Push to students.” • Student opens the app on an Android tablet or any modern mobile browser, enters their PIN, and is taken straight to the chess puzzle—no menus or extras. • The Teacher dashboard instantly updates, marking each student as “solved” or “pending.” What I need delivered 1. A clean, touch-friendly UI (tablet first, phone friendly). 2. Working demo APK and responsive web build. 3. Very small back-end or realtime service of your choice just to store the puzzle and completion flags. 4. Short setup/compile guide so I can re-deploy it for the school presentation. Acceptance criteria – Teacher can push one puzzle and view live status. – Student sees only the pushed puzzle after PIN entry; all navigation and OS controls are disabled or hidden. – Runs without crashes on standard Android 11–14 tablets and Chrome mobile. – Looks polished enough for a classroom demo and stays within the modest budget envelope originally stated. This is strictly a demo, not a production system, so lean solutions (Flutter, a small React PWA, or similar) are welcome. Please schedule the work so everything is ready before 1 April 2026.