Problem with float and centering containing element

I am having an issue centering the container for my body elements (content and sidebar). I have it set as – margin: 0 auto – but seems to be favoring the left side of the screen. I want it so the body elements remain a fixed width and the margin shrink as the screen adjusts.

If someone can help I would greatly appreciate it.

My site is buildthefire.com

Thanks

[Please do not create duplicate threads – http://ww.wp.xz.cn/support/topic/issue-w-margins-for-non-responsive-site?replies=3 ]