It is actually possible to do this - I had forgotten that there is a "current path" set of classes. In the standard stylesheet_categories_dressing.css, find this section
Code:
/*change bullet when a category w/o bg image is open to subs:*/
#categories li a.cat-parent-text {
list-style: square inside url(../images/bullet2.gif);/*change to list-style: none; to remove bullet*/
}
/*change bullet when a category w/o bg image is open to products:*/
#categories li a.cat-selected-text {
list-style: square inside url(../images/bullet3.gif);/*change to list-style: none; to remove bullet*/
}
Add the desired properties, like
background-color: #aabbcc;
If you are using images or background images for category names, you will want to add rules like
Code:
/*change bg color when an image-replaced category is open to subs:*/
#categories li a.cat-parent {
background-color: #aabbcc;
}
/*change bg color when an image-replaced category is open to products:*/
#categories li a.cat-selected {
background-color: #aabbcc;
}
(Note that I have not tested these last rules, and they might need adjusting if used.)