[BAlexander]

I did find this piece of code in skin1\main.css

.menu-dialog .content {
border: 0px;
background-color: #ffffff;
padding: 8px 10px 20px 10px;
overflow: hidden;
}
.menu-dialog .content a:link,
.menu-dialog .content a:visited,
.menu-dialog .content a:link
{
color: #324c76;
font-size: 9px;

There was no font size originally in this code. I changed it to 9 to see the effects and it did change the category font size but it changed all the other menu font sizes as well.

I'm going to keep looking for a bit so if I find anything else I'll let you know.