superfish menu css problem

superfish menu css problem

I am using superfish menu on the site below.
http://sosbilens.ankara.edu.tr/superfish/example.php

my problem is as you can see, when I go through the sub menus. parent menu item's "a color" turns into white again but not background color. then nothing is seen. I want it to stay as first hover condition (white bg and black text) when I walking through sub menus. I cannot override it.
any  help will be appreciated.