You have a ton of html errors in that page, over 150, structural defects in your code can lead to all kinds of display issues between browsers. Try clearing up all of the issues listed here: http://validator.w3.org and see if the page starts reacting correctly.
You also have some errors in your css, including a missing end bracket around your Desktop media query.
If you clear up all of the code issues, and it's still not showing correctly, post back and we can take a closer look.