Don't you just hate that!
Just a note to anyone else looking at changing their colours and or font sizes. These can mostly be found in the CSS scripts, and on odd occasions I have found them in templates. Chang these may also affect other areas of your style. Like changing the search bar background colour, may influence the background to your calendar or widgets.
I found it much easier to just write your own bit of insertion and place this in the additional.css. As mentioned above.