How to do unequal auto margins

[dings]

folks! I'm tweaking this Wikipedia skin file, so the content of all pages I see get centered with a fixed width. I've done it as well as it's possible, I think. (It only works in my account, since it's my file. You can try it in yours, of course.)Since I use \[code\]margin: 0 auto\[/code\], the left and right margins have the same size. I don't want that, because the text appears slightly moved to the right (the div doesn't include the left bar). Rather than writing a whole new skin, let's do it the cheap way: I want to set the margins to 40% the left and 60% the right.Now, I can't use fixed (\[code\]25px\[/code\]) or relative (\[code\]40%\[/code\]) margins, because then the margins would appear even when the browser window is narrower than 750px (plus the left bar).So, I want the margins to be unequal 60% / 40%, but still automatic. Is that possible with CSS? Thanks!