I want to change the width of the margins on either side of the main content in my Default Theme - the one by Michael Heilemann - I think this is known as the "Kubrick" theme.
I'm not trying to change the overall width of the theme or the relative size of the sidebar vs the main content. I just want to change the left and right margins around that content, in other words the whitespace on either side of the content.
Where in the CSS is this set? Thanks in advance.