Top Bar Menu - Need hamburger format for mobile

For this site, I have set up the heading as follows:
Appearance > Customize > Header > Top Bar Layout: 1 column, Menu

In mobile, I would like the menu to be a hamburger format. However, I cannot find the control for this.
I checked the CSS, but did not see any code that would prevent or add the hamburger
Web Site:
https://acicomms.com/
BB Theme version: 1.7.4.1