Amazingly, Firefox retained this performance edge over Chrome for 5 years, and will likely retain for 5 more years. This is really an amazing technological achievement.
> Firefox's Stylo engine is fast. Like, really fast. Like, so fast that, if every browser were like Firefox, there would be little point in discussing style performance.
I recently had to debug and profile an edge case with certain CSS that made applications using our library somewhat slow. And it all was due to style recalculations. Interestingly, it was mostly a Chrome problem and Firefox had not a single element style-dirty, let alone 8000 of them (which was basically all of the DOM in my test case). While I could coax Firefox into also considering all those elements as dirty, recalculating the matching CSS rules took just a fraction of what Chrome took. Was a fun learning experience in how browsers work.
> Firefox's Stylo engine is fast. Like, really fast. Like, so fast that, if every browser were like Firefox, there would be little point in discussing style performance.