something wrong with categories list

There’s something wrong with the way my category list looks. In Firefox, it has a grey dot above it, like the title is part of the list too. In Internet Explorer the dot is next to the title. I’m not too sure of how to get rid of it, and I’ve tried lots of different variations of the php code (My sidebar doesn’t use widgets), but it’s always there for some reason.

This is the code I use to put the categories list in my sidebar:
<?php wp_list_categories('show_count=0&title_li=<h3>categories</h3>'); ?>

This is my website: Rinato

Any help would be much appreciated!