Upgraded to v10 and now media queries aren't working.

Question

I upgraded to version 10 and the media queries are not working on a new site I'm working on . They worked fine on 9.01 and still are working fine on another machine that has 9.01. But not in 10.0.
It doesn't matter if its a <link> Media query or a @media screen. They are not working!
I tried to reinstall and I'm getting the same result.

Answer 1

I have test my site and queries in all the browsers and Firefox is the only one acting up. It worked in v 9. It's like they are being ignored. Here's an example of a media query.
I'm testing by resizing the browser window and also by loading a site through an iframe.
@media screen and (max-width: 800px) {
body { background: #ddd; }
Can someone please get this fixed. Mobile designs rely heavily on css media queries.