This is OrangeMix, a dark color theme based on the color orange.
The reasoning behind this color theme is summarized in Designing OrangeMix. Please see Enhancing code readability in Code for more tips on improving code readability in Code.
Most formatting rules in the theme are language independent and should work as long as Code has grammar support for the specified language.
I gladly accept issues or PRs for improvements and changes. Please do fork off if you rather want to create an even better color theme of your liking.