dont use px for zero,
and just a trick, if your all values is equal to eachother than just write one of them not all of them (eg margin:0
@ecntrc, margin-left, margin-right, margin-top, margin-bottom, those values are still available in css but meaningless to use them since margin: 1px 2px 3px 4px; would mean 1px from top, 2px from right, 3px bottom, 4px from left.
margin:0; would mean zero for all sides