Exclude sub menu items

Hello,
First of all thank you for the nice module.
I am using Cufon for styling my navigation (menus)
For example I have the following structure:

- Home
- Projects
\--- Project one
\--- Project two
\--- Project three
- Events
- Contact

I am using the standard Drupal menu block and "Project" menu item is always expanded.

I would like to be able to style parent menu items (Home, projects, events and contact) only and exclude all the children items (Project one, Project two, etc.) from styling.

I have tried using "not" in my selector but still no luck:

#navigation #block-menu-menu-main-navigation ul li:not('.expanded ul')

I was wondering if someone can help me on this?

Many thanks