[Man Eating Duck]

Originally Posted by Agama

I wasn't referring to occasional superscripts but something like the Bible which has verse references as superscripts throughout. For such an exceptional case of superscripting it is definitely worth specifying a line height, otherwise the text just looks a mess.

Ok, granted, but formatting a bible is a pretty exceptional use case. As implied in my OP, the target group for my list is the "cookie-cutter" creators of retail epubs, for which I still recommend not changing those values. For highly specialised tasks you will of course have to make your own decisions, and not just regarding line height

There are also CSS tricks you can employ to make superscripts behave better, but AFAIK you won't get them to render completely correctly regarding line height.

Edit: Ninja'd by SBT

Originally Posted by SBT

I've ended up instead redefining superscripts, something like

font-size:0.6em;
vertical-align:top;

I might add that some very quick testing in ADE seems to indicate that it might render even better with a superscript span with line height of zero (So much for my crusade against ever changing line-height...):

span.ebook-superscript { 
    vertical-align: super; 
    font-size: 0.6em; 
    line-height:0;
}

and html

a footnote after the following word<span class="ebook-superscript">1<span>

I shall add this as an exception in my list