This site is a set of free study pages. It has no ads and no cookies. It counts visits in a simple way that does not identify you.
We count visits with GoatCounter, a small open-source counter. It counts two things, and nothing else.
Each count also notes a few general facts. These are the link you came from, your browser and system, and your screen width. They also include your language and your country, worked out from your IP address. GoatCounter keeps only totals of these.
It never stores your IP address. It holds your IP address and browser in memory for up to 8 hours. That tells new visits from repeat ones. Then it forgets them. Nothing is written to disk.
No cookies are set, and nothing is saved in your browser. That is why there is no cookie banner. Counts are never linked to your sign-in. GoatCounter shares nothing with anyone else. Its own policy is here.
Your reading progress and quiz scores are stored only in your own browser (localStorage). They never leave your machine. Clearing your browser data clears them.
Sign-in uses Google via Supabase, solely so your learning journey can follow you across devices. What gets stored: your Google account's basic identity (name, email, avatar) and your progress records (which chapters you've completed, quiz scores, how far you've scrolled). Nothing else. You can sign out at any time; ask and your stored data will be deleted.
The on-page assistant will run on an API key you provide. The key is stored in your browser only and sent only to the model provider (Google) with your questions and the relevant chapter excerpts. It never touches our servers — we don't have any.