It can be any color. Colors such as white, red, blue, or black. For instance, I choose white because it's describes everything about it. What about you?
I wanted it to be Blue, because it represents calm. But a better representation would be red and black.
Blue and red, with a little bit of black thrown in.
Green or black...I'm not sure.
Orange. Always has been, always will be.
EDIT: Then again...
black and red