Style integration from other modules?

I'd like to track clicks on cbox buttons in colorbox. It looks like I can do this with a custom style, but I'm not sure if this is the best way to do.

However if this is the way to go, how can GA module provide a style for colorbox? I guess it's best to maintain in the ga module, but users should not made to copy it manually to colorbox module folder as this is also dropped with every colorbox release.