[stonezafu]

In the template I use, there are two main controlling stylesheets:

1. main.css (in /skin/common_files/css, and
2. altskin.css (in /skin/fashion_mosaic_grey/css)

I imagine that most templates must make use of both (plus IE variants). The altskin.css modifies (i.e. over-rules) main.css much of the time.

I've sometimes found there's what feels a bit like a tug-of-war going on between the two stylesheets. That's where it's really helpful to use some sort of 'Inspect Element' facility in Chrome, Firefox or Opera to unpick what's going on. [I know it's there in IE, too - but I only use Windows to check how the shop appears on that platform. I'm a Linux man myself & use my wife's Mac to check Safari, etc]

Of course, just setting the width wider is only the start of your fun, as you'll no doubt need to amend settings for the various page sections, too. You have to see the page as a series of box containers within box containers, and it's easy to get lost as every page is made up of multiple template fragments. Again, using Inspect Element is helpful here - and using Webmaster Mode can help you see which template relates to the box section you're trying to change.

Make sure the site you're fiddling with is a copy, not live, and I recommend using a CVS to make sure you can undo the inevitable blunders.

Good luck, John