nav-bar style by Joel Birch - beginner help please

nav-bar style by Joel Birch - beginner help please

Hi all........Hope someone can help me out here.
I'm using the nav-bar style code by Joel Birch, but i'm struggling a little with it.
 
I'd like to change the width and bg colour of the top level and child level.
I've attached a screen grab to illustrate.
Also, if anyone else has examples of using this code, it might be a great starting point for me.
 
Thanks in advance
Andy