Sidenote and credit: Discovered this via this excellent story today:

Color Formats in CSS

https://www.joshwcomeau.com/css/color-formats/

https://news.ycombinator.com/item?id=34183663

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Edit: I unearthed two previous submissions with discussions.

Adding 'rebeccapurple' color to CSS Color Level 4 (2014) - https://news.ycombinator.com/item?id=9565503 - May 2015 (33 comments)

Adding 'rebeccapurple' color to CSS Color Level 4 - https://news.ycombinator.com/item?id=7924677 - June 2014 (25 comments)

p.s. there are a lot of neat submissions for the meyerweb domain, for example:

CSS4 Color Keyword Distribution Visualization

https://meyerweb.com/eric/thoughts/2019/03/29/css4-color-key...

See: https://news.ycombinator.com/from?site=meyerweb.com