Is there a way to change the "Responsive Menus Font Size" in the themes ?

- Yes, there is the easiest way to change the font size.

- Go to Customization >> General Setting >> Header >> Menu Setting.
- There will be three tabs are given General , Style & Responsive Menus .
- Click on Responsive Menu tab, there is the option "Menu Font Size".
- By using that option you can change the menu font size as per your requirement & also you will find more detail about this option in our theme documentation .