Showing up completely different on mobile…

The website I’m working on

http://www.peterbuffett.com/wordpress

should look like this when responsive:
(screenshot of desktop shrunk down to responsive size)

but when viewing on the phone looks like this:
(screenshot from phone)

The layout, menus, logo – it’s all completely different (like there isn’t a theme there at all). Can you offer any ideas on why this is happening? I can’t figure it out for the life of me! Thank you!