Formatting wrong on certain browsers, but not for other sites with same theme

Hi –

I am currently using Foodie theme on the Genesis framework. On certain web browsers my website formatting is just completely off – like there is no CSS at all. My sidebar goes down to the footer, my posts have no formatting – it looks awful. The weird thing is, other websites with similar formatting (and the same framework/theme) look completely fine on the SAME browsers (see picklesnhoney.com or faring-well.com). So I’m ruling out that the issue is the browser itself- because other websites with the same theme are fine. I’ve gone through my code and looked for any bad HTML (i.e. unclosed <div> tags) but can’t find the source of the issue. Any ideas?