mobile version not working

Site URL: http://youthrising.com/

Site functioning ok on computer, the mobile version doesn't appear to be working, it's just the full version. We set the settings as far as we can tell, as to the mobile menu, but it doesn't show. Also the main banner image doesn't scale down, any ideas. Using impact template.  

Impact, a member of the 7.0 Brine template family, does not scale down a banner image for mobile. It crops it. You can see that by looking at the demo in mobile view (you can do that from the desktop and Chrome by right clicking and choosing inspect ) Since it does that, it is very important to choose the correct banner image, with emphasis on the left side of the image. That can be seen in the demo as well. I have two sites using brine and had to be very aware of how it works and placement of my welcome page banner. Your menu is there in mobile view for me. It is not a hamburger with that template demo,  it is a plus sign which can be changed in site styles to a hamburger dots, two lines of text as well as other choice.  

https://impact-demo.squarespace.com/

You can try this code to make the image resize for mobile:

@media screen and (max-width:640px) {
.homepage .section-background img {
    width: 100% !important;
    height: auto !important;
}
}