[Jellby]

Originally Posted by phossler

.sup {
	vertical-align: baseline;
  	position: relative;
  	top: -0.4em;
	font-size: 70%;
	line-height:0;
}
.sub {
	vertical-align: baseline;
	position: relative;
	top: 0.4em;
	font-size: 70%;
	line-height:0;
}

The subscripts (using .sub above seem to sit on the baseline, and not 'sub' to it.)

You are relying on "position: relative", that's not a very wise choice... You should use "line-height: 0" with "vertical-align: sub" and "vertical-align: super" instead, or simply with <sub> and <sup>.