Wow, I hadn't realized the CSS revert-rule keyword (a feature I originally proposed, albeit with a different syntax) is now Baseline, as of Sep 14! 😍
Only 2y4m from initial proposal to Baseline.
1y8m if you count from the WG resolution!
Full timeline: https://lea.verou.me/specs/#revert-rule
This allows creating declarations with variables etc that disappear entirely when invalid instead of becoming IACVT, paving the way for real block-level conditionals.
Correction: @JaneOri had posted an even earlier proposal for the same concept, 4 years before! I’ve now updated the data to include hers first: