Description of problem:
Various Bugzilla pages display error messages and other important information in (what I presume to be) black text on a red background.  For the 8% of males who are red/green colourblind, this text is difficult or impossible to read.

Version-Release number of selected component (if applicable):
5.0.3 (beta.bugzilla.redhat.com)

How reproducible:
Always

Steps to Reproduce:
1. Login as an admin user and go to Administration->Groups.
2. Click the Delete link for one of the groups.
3. Login as any user.
4. File a new bug, press the browser's Back button and submit again.

Actual results:
- In the page displayed after step 2, under the Confirmation heading there's a red box containing black text.
- In the page displayed after step 4, there's an error message in a red box with black text.

Expected results:
All page elements are readable for colourblind users.

Additional info:
Black on red does not provide sufficient contrast for a colourblind user to easily distinguish the foreground from the background.  If a dark background colour is used, a light foreground colour must be used to ensure sufficient contrast.  The converse is also true.