"It can also be used to extract the user’s IP address, user agent, and other identifying information." Not super shocking, given that most JS libs will gather this type of information, but very interesting to see this done via CSS which isn't monitored as easily.

Direct link to the code https://github.com/jbtronics/CrookedStyleSheets

Böhmer’s work is very interesting and I can see how this is difficult to prevent.