...but the problem seems to be that IE uses as offset of 1.0cm as the base reference offset. Means when you put 0.5, you are effectively to the left of the reference (-0.5cm) causing your setting to actually shift the stuff left. OTOH, Mozilla seems to use 0.0cm as the base reference, so using 0.5cm shifts things right.

The Mozilla behavior would seem much more logical - 0 is a much more logical starting point.

The addition of the .li tag just is meant to compensate for this - without being too noticeable on Mozilla.