A #css#hottake for y'all: I don't understand why so many people want nesting in CSS. The most useful bits of Sass nesting are BEM style selector extensions and @-query nesting. The former you can't do in the current Nesting spec, the later is nice to have but not enough to not ship new actual functionality to browsers. Creating complex selectors/long selector chains was always a nesting anit-pattern, and doesn't go away with the new spec.
I'm also concerned about how this breaks CSS's A+ PE
