[Alibizia Theme] Colour Problems

I am currently helping a friend with his website, which can be found over at cinematicvenom.co.uk.

He is using the Alibizia theme, and he wants me to change the colours of the menu from what they are now to a black background and black border with white text.

However, all I can manage is the background. Since he is using the ‘Goblin’ colour scheme, I looked through the CSS file for it, but couldn’t find any way to change the other colours I wanted.

Short of getting him to install a new theme, how do I get this done? I posted on the theme’s forum, but nobody is getting back to me. I’m only posting here because the community is more active.

Also, I couldn’t see any settings in the theme’s option section of the admin panel.

Thanks for your help.