Theme not working in mobile device

Theme name: Primer
When I check the website in a desktop, every thing seems to flow nicely.
When I check the website in a mobile device such as an Iphone, the navigation buttons that are below the front main picture, are not there!. Also I set up a background picture that is fixed and on the phone is not fixed. If I don’t have the navigation buttons showing up below the picture then people watching the website in a phone will not be able to navigate. I was able to get navigation buttons at the bottom of the whole page, but that is not the problem. Any suggestions would be really appreciated.

Thank you

The page I need help with: [log in to see the link]