this really depends on how you are implementing the code... using your
previous code sample from this thread
http://groups.google.com/group/blueprintcss/browse_thread/thread/5b1c12b31996d29a....
I would remove the span-24 from your custom divs (head, infocontainer,
content, etc) which would remove the float:left setting and then you
could just apply the border to these divs. The other span-# divs will
determine the width of columns... it's redundant to always include the
span-24 on multiple divs.
This may not be the most technical explanation, but it's the way I
usually think about it. Maybe Christian could give a more technical/
precise explanation?