Is there a way to change UI colors?

[doolhoofd]

Adding a similar request regarding the color scheme of the UI, posted earlier today by @Ayjjala:

The interface in six different ways . . .

I like the style of the interface (simple and richly-colored) but it’s also too simple (not completely functional by range - for the window and for the content) and mono-chromatic with no options (color can affect mood).