Modifying menus to have a line under the last item (or a dropdown box)

Y'all:

I'd like to have a line under each menu item in the drop down, to better separate the menu items from the page that's under it. I've tried this:

ul.rMenu li a:link,
ul.rMenu li a:visited,
ul.rMenu li a:active,
ul.rMenu li {
border-bottom-style: solid 1px;
border-bottom-color: red;
}

To no avail... Another possibility would be to have a box around the entire drop down when a menu comes up. I don't want a box around each item individually, if possible...

Any ideas?

Russ