Change Hover Color On Navigation

Here is the website… http://www.inboundify.com/

It’s not my site but I am helping work on it so I can learn some stuff hands on. I need to change the hover color on the navigation bar (where it says Home, About, etc). I was able to change the hover color on other stuff with the accent color in customize appearance but I can’t for the life of me figure out how on the navigation. I would like to change it to a green color and not the white that obscures the text.

Thanks for any help I may receive.