The colour scheme refers only to the ‘Members Menu’ that you see when you go to Add or Event your events or Profile. By Default it is dark, almost black, but you can change it.
Once logged in, click on My Profile.or My Events and you will see the ‘Members area’.
Click on My Profile on the main site, and it will take you straight to your Profile screen. From there you can choose from the pre-selected colour schemes. Just click ‘Update Profile’ at the bottom of the screen.