[totaltec]

My original design for the responsive template used separate style sheets for the different device widths. Since then it has been replaced with media queries as you suspect. There are separate sections in altskin.css for 1200, 960, 700, and mobile width. You can find the sections clearly marked in the file.

Of course, it is not too hard to get the same result with media queries rather than separate style sheets, you just have a very long CSS file, but the effect is essentially the same. The html templates are shared. I like responsive design due to the full website being available on mobile, rather than a stripped down version. It offers the best user experience in my opinion, they know what to expect and how to find things whether they are at home on the laptop or on the road with their phone.

There is also a mobile mod for X-cart that separates the skin files. I don't have much experience with that yet, I usually convince my clients to go responsive.