color: color(display-p3 1 0 0, green) This should show red when display-p3 is supported, and green when it isn't. Instead it shows black. data:text/html;,<body%20style="color:color(display-p3%200%201%200,%20green)">color</body> --- https://www.w3.org/TR/css-color-4/#color-function 10.1. Specifying profiled colors: the color() function The color() function allows a color to be specified in a particular colorspace (rather than the implicit sRGB colorspace that the other color functions operate in). Its syntax is: color() = color( [ <ident>? [ <number>+ | <string> ] [ / <alpha-value> ]? ]# , <color>? ) The color function takes one or more comma-separated arguments, with each argument specifying a color, and later colors acting as "fallback" if an earlier color can’t be displayed (for example, if the colorspace it specifies hasn’t been loaded yet).
<rdar://problem/63248585>
Created attachment 399462 [details] [Patch] WIP Needs tests, but I think I have it working :)
Fallback colors have been removed from the spec.