I can never remember the order of the shorthand property for setting the margin or padding in one declaration. That is:
margin-top: 2px;
margin-bottom: 4px;
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Think that you're reading Arabii or Hebrew: read from the top of the page, right to left to the bottom. ;P The good thing about this "rule" is that it works for the 3 value version too:
top right-and-left bottom
Actually, i allso thought it was hard to remember, but as soon as I discovered it was the direction of the clock it was easier.