So I’ve tried to get custom prop in a bunch of variations of
getComputedStyle(document.querySelector(":root")).getPropertyValue("--uxp-host-text-color")
getComputedStyle(document.documentElement).getPropertyValue("--uxp-label-color")
// ...
No luck - I always get an empty string. Does UXP support that at all?
As a workaround I get the theme with batchPlay, but I have no idea what actual colors are depending on the themes 