bullets in the theme

I'm not sure how to doument this, but i hope this is the right place for it - and i hope it is of interest.

I have added the following lines to the style.css file
__________________________________________
li.leaf {
margin: 0 0 0.35em 10px;
list-style-image: url(images/bullet_diamond.gif);
list-style-type: disc;
}
li.collapsed {
margin: 0 0 0.35em 10px;
list-style-image: url(images/bullet_plus.gif);
list-style-type: square;
}
li.expanded {
margin: 0 0 0.40em 10px;
list-style-image: url(images/bullet_minus.gif);
list-style-type: square;
}
_____________________________________

and now the tree structure of the theme works better in the sitenav section.
I actually know very little about CSS, so please check if it looks ok.