Dark Mode or Eye rest mode !!!!
Well like you tube you have Dark Mode and im on this 247 making maps and ideas for my work. My eyes hurt. If their was eye rest. Or a Dark mode would be amazing !!! Please Add
Seanny Murakami commented
You can adjust the background color using Stylus https://github.com/openstyles/stylus
Alternatively, if you're asking about themeing, see related https://mindmup.uservoice.com/forums/200447-what-should-we-focus-on-next/suggestions/11166246-themed-color-palette-in-mindmup-2-0