if your template is based on the default template all you need to do is go into
/includes/templates/your-template/css/stylesheet.css
substitute your-template for the name of the template you are using, eg soft-metal, cherry-zen, etc
add this code right at the very bottom of the stylesheet.css
.categoryListBoxContents {
font-size: 12px;
font-weight: bold;
}
and play about with the font size till you get the size you want in pixels, eg 12px, 10px what ever you want really
save the file and return it to your server, job done
