Looking through my code, I don't see anything targeting
.btn-header. Was that something you wrote yourself?
.btn-header also has the
.btn class, in which case the other CSS rule you show will change it's color without you adding anything else.
Would you mind copy/pasting your code into the forums here? I think I need to know a few more things about your code before I can answer that.
See here for how to make it show up properly: