I see it got lively whilst I've been asleep!
@speakingtohe, Try googling 'CSS Specificity' if you want to know more about the problems being discussed here. But I warn you, it isn't a gripping page-turner
The other problem is that even if you do have a perfect understanding of specificity it doesn't mean that it's possible to create something in the extra_css which will work for all your epubs. It will just help you understand
why it's not helping - not much consolation.
@Geoff, David, I have previously tried the
p {line-height 1.0 !important} trick but it resulted in the whole epub being displayed as if it didn't have a css file. I've just tried again with 3 random epubs - same result for all of them. Have you tried it with success? I had assumed (perhaps wrongly) that the !important in the extra_css may be conflicting with the several !importants Kobo have hard-coded in the fw (libnickel.so.1.0.0)
I don't see how it's possible to predict all the class names that may be assigned to any epub's 'standard paragraph' let alone
every epub's standard paragraph.
Whether the plugin should allow line-height to be treated exactly the same way it does widows/orphans and @page - I'm not sure. I know
I wouldn't use it because of the display problems Geoff pointed out -- but as long as users are told the pitfalls... People like me just wouldn't add a line-height setting in the extra_css and those with a strong preference the other way would.
P.S I forgot to say that the reason I included body.calibre, body.calibre1,... etc in my suggestion is that it's slightly easier to hazard a guess at the class calibre might use with the <body> tag. However, if you do conversions of conversions of conversions... maybe the calibre
nn class just keeps increasing into double figures. Of course, my suggestion is only going to work if there aren't any line-heights set lower down the chain on <p>, <div> or even <blockquote> classes.