[css-color] . 12-Bit deep color support.

With upcoming 4K and OLED monitors, with 10 Bit support, it eventually would
make sense to extend the web-colors to 12 Bit.
Currently webcolors are defined 8 Bit - 'web' sRGB (like: #FFFFFF or
rgba(255,0,0,1) )
So I propose adding something like 12-Bit 'extended-web' sRGB where you
define colors like:
*	X#FFF FFF FFF - instead of #FF FF FF
*	Xrgba(255*16,0,0,1) - instead of rgba(255,0,0,1)
Supporting just 10 Bit (what is actually just needed by upcoming displays),
would be quite difficult because of the poor 8+2 Bit format,
so the color white would be X#8FF - instead of X#FFF or #FF
 
Daniel Beckstein