You will find the setting inside Customize >> Colors
Background Color – This allows you to choose a background color for the sub-menu.
Text Hover Color – This allows you to choose a text hover color.
Background Hover Color – This allows you to choose a background hover color.
Sub Menu Font – This allows you to select font properties for the site’s sub-menu.
Select Font Family with Variant
It also allows downloading font family to the server instead of using the Google CDN.