How do I keep borders from changing in page break preview?
 

I looked at my spreadsheet in page break preview and the column headings were
abbreviated. So I auto fitted the columns. Then the right side of the
spreadsheet wasn't in the print preview. So I moved the pagebreaks. Now some
of the interior lines are fatter than others (every 3-4 lines). I tried to
change that, and I couldn't. The lines look fine in normal view, just not
printed. Any clues? (I have a recent version of excel.)