simple tree menu css issue

[AdamMMA]

Script: Simple Tree Menu
http://www.dynamicdrive.com/dynamicindex1/navigate1.htm

I am working on trying to style the simple tree menu using css and I cannot seem to specify the height of each <li> item to be 25px. Simply adding the {height: 25px} property works for the top level <li> items but the the layout is broken when opening the nested <ul>s.

Anyone know how to do it?

Here's my page: http://adammma.tripod.com/simpletree/index.html

Thanks in advance.

Adam