I know this is a privacy nightmare but also kinda... cool? Or at least interesting. I don't think I would have thought of this. 1. Measure element dimensions a

I know this is a privacy nightmare but also kinda... cool? Or at least interesting. I don't think I would have thought of this. 1. Measure element dimensions and detect installed fonts (measure a piece of text with specific a specific font to see if its installed) 2. CSS functions (e.g calc) that produce different results across browsers/systems 3. Detecting browser-specific CSS property differences (e.g render a file input, measure it) seems like you have to allow `@container` checks or something similar for this to work in order to then make your network request `#something { background-image: url('/x-browser-y-os-detected'); }`