Yeah totally understand this, at the moment there’s no way to directly override any of the secondary variables we automatically generate because those are all set in stone when the CSS is built. So in the short term, you will need to manually make these changes.
The color schemes are meant to be a super-simple way to define colors, and anything more specific than that needs to be custom CSS. This was discussed a bit more here: Customizing colors
Some things for us to think about:
I don’t think an advanced color scheme editor that grants access to override those secondary variables would be a bad idea, but because they’re used so broadly you’d likely need to write some CSS anyway.
So for example… you might want to override all text occurrences of $primary-medium… but it’s also in places for borders and other elements where the higher contrast $primary-medium wouldn’t be desirable. So at best an advanced color editor would reduce the custom CSS needed, but wouldn’t eliminate it entirely.
That being said… the primary issue here is text contrast for accessibility, right? Our default styles do fail for text contrast in some areas, and it’s possible that if we improve there this wouldn’t be a problem for you to begin with…
So I think in the near future our team can look at default text accessibility, and further down the road we can look at improving our color scheme tools to consider accessibility (Color - Cloudflare Design is cool experiment that factors in text contrast, for example).