How can I edit the .css for a widget?

I’m trying to get a site together using marketpress and the SimpleMarket theme.

I’d like to use the Product List widget to randomly display some things in the sidebar.

As you can see when you look at the site, the product names are too large. I’ve searched through every file and simply can’t find where to edit the size of that text.

It doesn’t matter what theme I use, the product name is too large when displayed via the Product List widget.

I’m a novice user of wordpress.

Any advice? Thanks!