Here is my site: http://www.parentcity.org

Here is my site:
http://www.parentcity.org

I am in the process of changing my theme. I would like my menu to act as this one does:

http://www.hughandcrye.com

When it is hovering, there is a black line below it. Please note, that I do have sub-categories so I would like them to do the same--once a category is hovered over the black line appears. Same as this menu:
http://withart.visitphilly.com

BUT I have drop downs, so want whatever they are hovering over in the drop down, to then have a line below it to indicate they are on it.

Thanks in advance!