Creating a custom color scheme is great, but how do you retain that color scheme?

The problem is... when I change style.css I have to revert back to default/standard theme.

Then I have to rebuild the custom color scheme anew.

It would be nice if we had a color folder arrangement for each color scheme.

Then we could alter or create a color scheme and continue to reuse it, if if we had to revert back to other themes to set new CSS.