My first responsive theme is driving me nuts!

I started off with a fixed layout, then converted this into a fluid layout with min-width. From here I placed some media queries for the widths of various devices, starting off with the smaller device first.

The issue I have with FF is that it does not go down to 320px width, something is stopped it. There are so many browser inconsistencies.

The link to the web page is here, still not sure what's up with it. Any helps, comments and suggestions would be greatly appreciated.