All this CSS minimalism reminds me of Dan Luu's post about Web Bloat: https://danluu.com/web-bloat/ His website is refreshingly light and fast, but that's still no excuse for Times New Roman. Maybe it's a retro irreverence thing.
Fixing this in Firefox is as easy as opening about:preferences in a new window and selecting your preferred sans font. Dan's site will instantly be transformed, and every other site like his (e.g. http://cr.yp.to/ https://motherfuckingwebsite.com etc) will be rendered similarly for all future visits.