CSS: Doesn't know color-schema

[Croydon]

URL being validated or code to reproduce error:

:root {
    color-scheme: light dark;
}

error: CSS: "color-scheme": Property "color-scheme" doesn't exist.

https://developer.mozilla.org/en-US/docs/Web/CSS/color-scheme#adapting_to_color_schemes

[aparcar]

This affects me, too. What's the solution here?