<< For buttons and things like that, you have to edit the moi.css file inside of a text editor, there are declarations of various rgb colors inside that file, you edit those rgb colors (yes, by editing the text) to change the UI.

Yes that ! :)
But it's that who is very painful !
With friendly interface for choice colors that will be more funny! (like yours for the Gride and Background's color)
ANd with with some complet presets it will be the top! :=)