I have: I have several web pages both with this outline:
CONTENT
I don't know about pure CSS solution, but you can use javascript to dynamically count and adjust correct width of left margin (while making the right margin a bit thinner - by size of scrollbar).
BTW: IMO: The correct way of dealing with this is: Leave it as it is. Because it is a default behavior and I don't think that users are worried about this as much as you are. This is my opinion and someone might have different one, but adding scrollbar to every page (to solve this) is epic fail. :)