Aha!
A little bit of fiddling and I have a topic page that I like the look of.
It renders fine in FF and IE6, but not in IE7. Why, I’m not sure, but I’m happy enough with it.
FireBug is really incredibly useful. I used it as you suggested and it does indeed make things a little faster.
It would be nice if you could export the style.css after you’ve finished modifying it in their nice user interface, but that’s minor.