Main Menu Fonts
To change the fonts of your main navigation head to Theme Options > Typography > Header. In here there are a variety of options for you to choose from which allow you to style the typography of your menu exactly how you want.
Header & Menu Colors
To change the color for your menu links head to Theme Options > Styling > Header Colors. At the top of this section are some options for you to choose your navigation's colors, also note that for the transparent header menu item colors to work, you’ll need to have a Transparent Header enabled on a per page basis (within each individual pages settings, we'll get to this soon).
Below the options for your main navigation's colors are options to style various different elements proprietary to each header style. These colors will obviously be active dependent on which header style you have selected to use.