My apologies for the delay in responding to you. I've been looking into this and candidly, trying very hard to replicate it on one of my own sites. I cannot, for the life of me figure out why this happened. From every possible technical angle, an installation of iBlogPro4 should not experience any change in the color scheme as a result of upgrading WordPress to version 3.3, yet in your site, clearly the colors are inverted. We have thousands of clients still using iBlogPro 4 and of course we'll continue supporting it fully. PageLines Framework, with the iBlogPro5 child theme doesn't alter our dedicated support for existing products.
The only things I can conceive of are that either there is some custom code added by you or a plugin is creating some conflict. I'd suggest doing several things. First, deactivate your plugins. You can do this one at a time and do a hard refresh on your site to view how the deactivation affected the colors or all at once and one-by-one re-activate, again checking in the same manner to identify which plugin may be causing it. The other thing to do would be to go to http://www.wordpress.../extend/plugins
and look up each plugin you have installed, whether active or not. Check for compatibility, complaints by others, whether others say it's working and the age of the plugin.
A telling tale of your problem and why I believe it could be a plugin is that the problem happened with an upgrade of WordPress. That indicates that something, as yet still unidentified, does not work with the new structure of WP 3.3. Once identified, if there is an outdated plugin you should leave it deactivated, find a replacement and then totally remove the deactivated, outdated plugins.