[Theme: Titan] Trouble customizing submenu

I’ve been banging my head against a wall trying to change the font color in my drop-down submenu. I’ve looked at the inspector, and I thought I found the proper identifier, but I still have no luck. I’ve tried all kinds of identifiers/combinations. It could be that my CSS is a bit (very)rusty, but can anyone help me out?
Here’s my site: artdecodaveapts.wordpress.com.

This is the code I was using in the custom CSS to change the submenu appearance:
#nav ul li ul li {color:rgb(152,152,152);}

This may be a stupid question, but I cannot figure out the proper identifier to use to change the submenu font. Please help!