Privacy
What this site collects, and what Google Analytics collects.
Updated
The site has no accounts and no forms that store what you type. Its only tracking cookies are the Google Analytics cookies described below. The self-test on each labeled drawing runs entirely in your browser and keeps nothing.
The site keeps one thing on your device, and only if you ask it to: when you choose light or dark with the switch in the header, your browser remembers that choice in its local storage. It is never sent anywhere, and clearing this site's data in your browser removes it. Until you use the switch, the page is shown light.
The site is served by Cloudflare, which processes standard request data (such as IP address and browser type) to deliver pages and protect the service.
Analytics
The site uses Google Analytics to count visits and see which pages are read, which helps decide what to draw next. Google Analytics sets first-party cookies named _ga and _ga_ followed by an id, which tell one visit from the next for up to two years. It records the pages you view, the page you came from, your browser and device type, and your approximate location (country, region or city). Google Analytics 4 does not log or store IP addresses. The visit records are kept for 14 months, then deleted.
I see only totals and trends, never who you are, and I do not combine the data with anything else. Google processes it as described in How Google uses information from sites or apps that use our services.
The site shows no cookie banner for now: analytics loads with each page. If a consent message is added later, this page will describe it first. To stop analytics, block cookies for this site in your browser, use a content blocker, or install the Google Analytics opt-out browser add-on.
If advertising is added later, it will be served by Google AdSense with a consent message for visitors in the EEA, the UK and Switzerland, and this page will be updated before any ad appears.
Questions go to the contact page.