Do you test the engine against acid3? I think what we need would also be something like acid4 as a test suite, because CSS4 with its flow-root rework is kinda

Do you test the engine against acid3? I think what we need would also be something like acid4 as a test suite, because CSS4 with its flow-root rework is kinda hard to implement for browser engines from the CSS2.1 age. Basically everything has been changed when it comes to the parser's grammar and lexical approach. Things like nested conditions in CSS through media queries or supports queries are impossible to implement without rewriting the parser from scratch. Do you plan on implementing all the event/media/supports related stuff from an isolated CSS perspective, including pointer events, transitions and animations? Because having the @supports queries unified across the board would help a lot supporting older browsers without animations or without a tweening engine.