Comment by snypher

>we only have three colour themes - standard, dark and high contrast.

>Theming Sonic Pi beyond this is only possible by hacking the source code and it’s not something I’ve had the time to make user friendly. However, if others would like to work on this, I’m happy to consider contributions.

This seems like a pretty reasonable statement from him; I'm sure others would appreciate the work, if you have the time.