Opacity Problems

I’m not sure why, but for some reason the opacity on my blog is messed up. Not always, just sometimes. In random places. I’ve gone over the CSS with a fine-toothed comb, and it looks fine, so I’m really not sure why it’s doing this. I’m gonna spend some time soon to try and fix it, because it’s really pissing me off. If you highlight a section of dim code, it automatically becomes bright and stays bright, so there’s almost some weird incompatibility going on with something I’m trying to do. It looks fine in Safari, just not anything Mozilla based.