Sass Color Spaces [WIP]

Historically CSS has been limited to a single color model (RGB) and gamut (sRGB). Authors have various formats to describe colors in that gamut – using cubic hex notation (#rgb/#rrggbb/#rrggbbaa) and functions rgb()/rgba()``, or cylindrical/polar-angle functions hsl()/hwb()`.

Unfortunately, sRGB is a relatively narrow color gamut, and RGB isn’t a perceptually uniform color-model. Many monitors (and some browsers) now support wider color gamuts (such as the popular display-p3), and there has also been significant progress in developing more perceptually uniform color spaces such as CIE LAB and okLAB.

The CSS Colors level 4 specification describes how CSS authors can access these newer gamuts & formats – with okLAB as the default space for color-mixing. We want to provide support for this in Sass: with server-side tools to manage colors across spaces, and convert colors between spaces where appropriate.

That includes support for all the new CSS functions, along with some additional Sass functions for inspecting and adjusting colors before they reach the browser. This requires rethinking the Sass color module from the ground up.