What do you mean by theme? If it's the skin that's on the default site, it's Dark - Orange. By the way, I'd take that banner out of your sig; it's considered advertising and could lead to a permaban.
The style is designed for Xerofono. It's full name is Flexile and the default version seen on EMC is Dark - Orange.
You see, under every post, on the right down-side, that says reply, that let's you quote, that is easier