Hello.
In this thread:
/t/Color-customization/8841/1
garlogan asked for a way to improve the contrast for the SRS level colours.
Here is a small script that changes the colours. It applies to the dashboard, profile page, and progress pages.
https://greasyfork.org/en/scripts/10491-customlevelcolours
It is not a full colour scheme customisation script but you can alter it if necessary by changing the colour hex values in the code.
Examples:
