.gif doesn't support true transparency so redundant colours will always occur on multple styles. There is an alternative you could implement replacement variables for each of the style Thread
located here. When you've implemented that come back with the other colour you want the alternative set to be.
edit: I knew there was a reason why I didn't save a set for dark styles. The set looks (in a nutshell) shit on dark themed backgrounds I wouldn't recommend using ithis pack on a dark style. In fact, I'm not sure i'll even make the modifications for dark backdrops because that's how bad the set looks on them.