In {Theme} you have option to customize the menu of the theme using the options you can check below. You will find them in the Customizer on path Navigation Bar > General.
Navigation Bar

Navigation Bar Customizer
The General options in the Navigation Bar will let you set the background image for the Navigation Bar and choose from one of the 6 styles.
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General
- Background image
- Background image repeat
- Navbar style
General Customizer