Mobile webpage different from browser

[protofrancesco]

Hello, I've successfully deployed my website; everything seems to work - tho, since I'm not a developer at all there might be few things to adjust. Anyway, the main thing I've noticed is that the mobile webpage does not seem to work as it should and it results different from the pc browser.

First thing I noticed is the font: I've changed it from the original one to Montserrat but on mobile it does not change. Also, Is there a way to add the burger menu for mobile?