[csswg-drafts] [css-color] 12-bit Hex Notation (#5344)

Crissov has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-color] 12-bit Hex Notation ==
I donʼt like hexadecimal triplet (or quartet) notation for RGB(A) color values, because I think it is 
firstly too opaque, in that for many people the _hex_ in the tech slang term “hexcode” resonates with _magic spell_, 
and secondly too technology-specific, in that RGB becomes constrained to 8-bit sRGB. 
However, it remains immensely popular, so take the following as an _advocatus diaboli_ proposal.

It has not been brought up as a part of #3249, but since each hexadecimal digit represents a nibble, i.e. 4 bits, a logical extension to #rgb (3 hexdigits, 4-bit channel or component, 12-bit color), #rgba (4×4, 16), #rrggbb (6, 8, 24) and #rrggbbaa (8, 8, 32) notations would be **#rrrgggbbb** (9, 12, 36) and **#rrrgggbbbaaa** (12, 12, 48). 
10-bit color channels cannot be represented well this way. 

Although #rgb can simply map unto #rrggbb or #rrrgggbbb by repeating the digit, this is not possible in general for mapping #rrggbb unto #rrrgggbbb. 

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5344 using your GitHub account