Sub Menu Background Color Change

Hi

I am trying to change the background color of the sub-menu but not sure where to do it exactly?
By default, the background color remains white or gray, in all your sample site.
The challenge is I am changing the primary menu background and text colors and want sub-menu to match it.
How do I change the background color and on-hover color of sub-menu?

URL - http://cms.demosites.info