How do I change the color of my profile?

[Mysterious Brute]

Read over the title it's pretty self explanatory.

[Bastion Hallow]

First off you should think about shrinking your signature since it stretches the board. But as for the profile...

Click

That tells how to update and modify the profile. It is a fair bit of coding. And if you are unable to do it yourself you might be able to ask around some and find others that are willing to do it for you.