1- Open the navigation tab: Select the navigation configuration from here

2- Navigation: You can change the background color of active items in the main menu, the Color text of the main menu, the main menu hover text color, the font size of the main menu, text font-weight, and row height b/w both menus

3- Flyout Menu: You can change the background of the main menu drop-down and the menu color, font size of the main drop-down, and font size of the main category