The baseline of superscripted text is aligned with a point above the baseline of the line box. This distance above should be determined by reference to the font itself. If the element doesn't have a baseline, its bottom is aligned with that point instead. The baseline of length-aligned text is aligned with respect to the baseline of the line box. This distance should be determined by the computed value for vertical-align.
Positive values raise the baseline, negative ones lower it.
Percentages relate to the computed value for line-height of the element on which it is specified. If the element doesn't have a baseline, its bottom is aligned with that point instead. See copyright document for terms of use.