Transition to hamburger menu

Hello,

I am using the Startup template on the following site:
www.diocesi.parma.it/parrocchie/sorbolo/
My top menu is quite large and when the screen size gets smaller the rightmost items of the menu are hidden. Then, when the size of the screen becomes even smaller, at a certain point the menu becomes "hamburger" style (as in mobile) and this is ok. The question is: how can I change the threshold (of screen size) for the transition from the "normal" menu to the "hamburger" menu?

Best regards,
Francesca

I found the solution... in the Templates: Edit Style ->Responsive.
So easy... Sorry for bothering!
Regards,
Francesca