Responsiveness not working in 2012

Hi,
I am using Twenty Twelve and it isn’t behaving as it’s supposed to. When I view my site on a smaller device or even resize the browser window, the CSS seems to break. I’ve taken out the drop shadow and re-aligned the logo in the center, among other things. When I make the browser window smaller or view on a smaller device, these changes disappear and everything looks awful.

I have a feeling it has something to do with the order of the CSS I’ve changed in the child theme or the media queries, but I’ve never done CSS before, so I’m not sure. I’m pretty sure my CSS isn’t the prettiest thing in the world, anyway…

The site is http://www.flouroflondon.com. Any help appreciated.

Thanks.

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