[SOLVED] Comment background color not taking - 3.5.3 on 3.01

I can't seem to get the color selections for the comments to turn out the way that I want them to: the coloration for the text ends up just fine, as does the avatars and author comment tracking. However, when I attempt to change the color of the background on the comments, they remain white.

This doesn't appear to affect anything else. I went so far as to delete my install of Wordpress, reinstall, manually uploaded 3.5.3, and then imported settings from a prior setup. I've tried it in both Chrome and Firefox (both latest versions) without luck. Needless to say there's no other plugins or themes that could cause conflicts, and in all other respects the theme is doing exactly what I expect it to.

I've tried resetting all theme options, then going back in and just altering the color for comments; this has no effect.