Wp List Pages CSS Selector issue

Hi I have a WP site here:

http://www.nourishnfp.com/dev/services/

I looked earlier on forum to find a way to highlight page nav if a parent page was selected. And found out how with the code below:

#nav a:hover, #nav a.active, #nav li.current_page_item a, #nav li.current_page_parent a  {
background-color:#8c0605;
color:#ffffff;
background-position: 130px -26px;
display:block;
}

Unfortuanely the selector #nav li.current_page_item a is also affecting my drop down menus as well which are a sub UL of my parent li..

Have spent forever trying to find the css selector that may over ride the above code…Cant seem to find anything that will do the trick??

I have also tried just using #nav li.current_page_item as selector which didnt affect my drop down menus but did affect the highlighting of main navigation item..

Advice much appreciated