I'm still not comfortable with using pixels for any measurement in an epub. The dpi for various screens goes from 100 (or less) for some lcd screens usp to 200 for a 5 inch E-Ink screen, and maybe more for a Retina display. The visual effect will be quite unpleasant.
And
I would use
margin: 0.5em, 0, 0; or margin 0.5em, 0, 0, 0; remembering that margins start aat the top and go around clockwise. A two valued margin doesn't do waht you want, and I always forget that it is the side margins that are duplicated with the three valued margin.
@yekim54 - You know he didn't try exactly what he typed with ADE
ADE would have thrown out his whole style sheet for that missing semicolon
