Privacy

Your progress (concept statuses; chapters, papers, videos and experiments you mark), your reading mode and your theme are saved in this browser's local storage. They stay on your device and are never sent to us. Clearing your browser's site data removes them; some browsers, such as Safari, also remove them after a period without visits.

The site's code includes no advertising or tracking scripts.

We store three things in your account:

• your email address (from Google, or the one you typed for a sign-in link), used only to sign you in;
• one progress record, the same data kept in your browser, and when it was last updated;
• the sign-in details the login service needs, such as when you last signed in.

Sign-in and storage are provided by Supabase. With Google sign-in, Google tells us your email address; we don't request your contacts, files or anything else. We don't sell, share or analyse this data, and we don't send marketing email.

On Your progress, Delete account removes your account and its progress record immediately. Sign out only signs this browser out; the progress in this browser stays until you reset it on the same page.

Questions about your data, or a deletion request you can't make from the site: write to [email protected].