CSS Color 4 adds oklch(): get wide-gamut colors including P3 (and beyond)

I am really interested in wide color gamut images for the WWW. Lately I've been making this kind of image

https://en.wikipedia.org/wiki/Anaglyph_3D

and tracking down some anomalies on my wide color gamut monitor I found that a sRGB anaglyph is degraded on a wide gamut display because the (0, 180, 0) green in sRGB isn't as pure as a (0, 180, 0) green on a wide gamut monitor and it gets transformed (by the web browser) to something more like (16, 176, 15).

Maybe that looks the same as the sRGB green but the extra red light goes through the red filter when it shouldn't, causing a "ghost" image to appear.

I think I can somehow publish a WCG image which will get closer to what I want on a RGB monitor but I'd rather do the anaglyph processing in WebGL. In my case conventional color management is not what I want, if I really want optimal color appearance I need to develop my own color grading system specialized for anaglyphs.