Plone CSS Modification and Information
If someone wishes to modify the settings of their Plone web page, and they are NOT in one of the COO's departments, it can be done by modifying the local Cascading Style Sheet (CSS) for their web page.
This will allow for modifications such as background color, text color, text size, fonts, etc.
You would have to change your text color and background color in your local CSS for the form item or folder. Please see the help site for more information on the local CSS
http://louisville.edu/web/helpcenter/plone-4-user-helpcenter/how-to/Use-local-css/view?searchterm=CSS
You my also join the WebGuide listserv and someone there might be able to give you some help as well.
This is the way the theme is designed to highlight groups of controls.