Change nav menu font color and face in Fixer theme

I am finding it very bizarrely difficult to change the color and typeface of the font for my main navigation menu (fixer menu) in the fixer theme. When I click on the menu settings, there is no option for css edits as some previous responses I found in this forum suggest there should be. Do I just need to edit my child theme?

My site is http://soul-archeology.com