Topic on Extension talk:CodeMirror

Pick better colors, where colors contrast more clearly and coincide less. For example there are four elements currently in the red/purple spectrum. Given a background color change, a dark theme should also be possible.

You can actually pick your own colors, if you want -- there's info on how to do it here:

https://meta.wikimedia.org/wiki/Community_Tech/Wikitext_editor_syntax_highlighting#Color_and_style_customization