"All our imagery is double-resolution, so everything looks sharp on high-density devices..."

But you also use normal resolution images, right?

Many (if not all) low resolution Android devices aren't able to scale images down by using background-size. Since it doesn't work, the UI gets blown out by huge images that haven't been scaled.

Just curious on that implementation detail since dual sized images for low to high res screens is something I deal with in my day to day mobile web work.

Nice work though. The mobile site looks really good.