@Reshiram110 poked me and a dark DevHub theme popped out. Enjoy.
The orange accent color can be externally customized with Stylus, however, every color is a variable, so if you feel inclined you can copy the CSS and manually tweak the colors to your heart’s content.
On my 720p monitor, contrast looks fine, however this may not be the case on all monitors. Let me know if you find serious contrast issues. Also let me know if you see anything weird. I’ve done my best to cover all major pages and components, but the DevHub will always be changing.
This theme should also be compatible with my compressed theme, sans the colored sections option.