Add to home screen
There's nothing to download from an app store.
Add this website to your phone's home screen and it opens full-screen, just like a regular app — same icon, no browser bars.
Troubleshooting
If you can't see Add to Home Screen, try refreshing the page, opening it in Safari on iPhone or Chrome on Android, or checking the browser's Share menu.
Why?
It opens full-screen with its own home-screen icon — quick access, no browser bars, and no app store account needed.