FWIW, Pavel, one of the authors, has devoted considerable time into what is one of the very, very few attempts at a formal specification for CSS (the static/float layout fragment cf [1]). It's a Racket program generating Z3 SMT solver code for verifying an instance layout (which also looks like Scheme) so it's not for the faint-hearted ;) but maybe just what an FP fan on HN is looking for as a challenge.
Wow, thanks, you always suspect no one has actually read the papers :) That was a crazy project... I eventually got it passing almost all of the WPT css2 fragment.
I'm still working on CSS layout, with hopefully another paper coming soon.
For what it's worth, I'm just a devops person and I found that article on How CSS Floats Work to be very understandable :) Thank you for writing all this great stuff!
In that case, you've got at least one avid reader ;)