nesting will be nice when it lands, but i'm most excited by far for :has() support. i know chrome and safari have initial implementations in place and firefox just recently started. :has() will be the biggest advancement in css since grid, moreso than nesting or container queries, because of the power it puts in the stylists' hands. unfortunately trying to track its progress is a haphazard gander into an opaque maze of different sites and bug trackers.