Nothing that identifies you is collected by the pages themselves. Every page is static HTML built ahead of time, there are no third-party scripts, and the typefaces are served from our own domain rather than a font network.
Our web server and reverse proxy keep ordinary technical logs of requests: the IP address the request came from, the time, the path requested, the response status, the user agent string and the referring page. These exist so we can keep the service running and investigate abuse. We do not use them to build a profile of you and we do not combine them with anything else.
Your theme and high-contrast preferences are stored in your browser's local storage under the keys uv-theme and uv-contrast. That is on your device, it never reaches us, and clearing your browser storage removes it.