In addition to the new upgraded forums, we also have an additional theme/skin that allows you to pick your own colors!
It's the IPB Unlimited theme that you can see on the dropdown menu
in the lower left corner of the forum:
If you prefer the original blue IP.Board theme, choose the IPB.Board theme:
I wanted green for mine, so I chose the IPB Ultimate (imported) theme:
Using the IPB Ultimate skin/theme, you just choose the little white paint brush in the right header area below the search and above the Recent posts: