CSS color overriding should be all or nothing

I'm developing a site for a client which will use a light-on-dark color scheme (it's a theme built off of Zen Midnight). Unfortunately, this causes some graphical ugliness and inconsistency with IMCE. The problem seems to lie in the fact that IMCE overrides most of its elements with stylesheets to create its standard dark-on-light color scheme, but not all of them; the other ones are targetted by rules in my stylesheet, which attempts to invert the colors.

The result is the attached. I'll probably end up fixing it by tweaking the rules in the theme's stylesheets so that IMCE's elements aren't targeted, but I'd rather not.

I think it would be preferable if IMCE either strictly colored all of its elements for a consistent dark-on-light look, or didn't color any of them and let the site's theme take total control.