I am using a separate style-sheet for printing. Is it possible to set right and left margin in the style-sheet which set the print margin (i.e. margin on paper).
I'd personally suggest using a different unit of measurement than px. I don't think that pixels have much relevance in terms of print; ideally you'd use:
point (pt)
centimetre (cm)
I'm sure there are others, and one excellent article about print-css can be found here: Going to Print, by Eric Meyer.