MarketPress Product list changes formatting from Store page

If you go to my site and view the STORE page, the center area is spaced well (see the small outline?) but once you click on and individual PRODUCT (not the main products list) or SHOPPING CART or ORDER STATUS, the central area shrinks. I am not sure how to change this so the spacing is the same as the STORE page . (It looks like it is indenting from the left or has a large left margin.) SHould I change this in the MARKETPRESS CSS? Or do I need to add a margin/formatting attribute to the main css for my theme?

Store Page (center area looks fine) :

Individual Product page (center is pushed to right and smaller):

Shopping Cart (also pushed to right and smaller):

You can see a lot of space between the nav bar on the left and the central area.