Make thread titles bold in forum - silly question?!

[pmdpmd]

I'm embarrassed to ask what seems to be such a simple question, but I have searched high and low and come up a blank.

I just want to make the thread titles in the list that's shown when you click on a forum bold.

The logical place I would do this would be in stylevars threadbit_font, but that doesn't exist.

I've tried every other likely looking _font stylevar including those in Common with no luck.

The only suggestion I could find searching the web was to change the Main CSS, but when I go to that vbulletin tells me it is now redundant.

Many thanks for any suggestions.

Paul.