Browser Page Resize Problem

I’m not quite sure how to explain this problem, but here goes:

I have my site set up how I want it, but the problem comes when I make the browser page more zoomed in, or less zoomed in. (I have a Mac, and I can adjust the browser size with the trackpad). When I make the site smaller, the content gets smaller, but the page width stays the same. Basically, all the content resizes, but the page width and boxes do not. I’d like to change this so that when I zoom out from my site all the content is “cemented” in place.

Does anyone know how to cement my content down?
You can see what I mean, here’s my site:
http://epicasiatravel.com/

Thank you!!!