Lewis said:
Really? Don't you have to specify a unit?
Or does 1.3 get translated to 130%?
It is almost always better not to supply units. Using a number
gets you a proportion of the font size. There might be special
cases where using units is what you want, but you need to be
aware of the consequences. Simple rule for most purposes: Don't
use units.
It works like this, no unit and the line-height gets to be a
proportion (yes, I guess a percentage) and, crucially, this gets
to be for all text that is in the element you declare it on *and*
in its descendent elements. That is usually fine. Because?
Because then, if the text is a different size (as set by the
author or by default) in the descendant elements, they will get
that proportion of the particular size and it should look natural
enough if the line height set for the original ancestor looks
natural enough.
If you use units, you can get a weird result in 'descendant'
text. This latter text, no matter how big or how small, will get
a line-height appropriate to the text in the original ancestor
but almost certainly inappropriate for text of a different size.
Imagine the result in the browser is roughly three pixels between
the lines of text in the ancestor. For text that looks fine with
this gap.
Now imagine how bad this will look for really big text in a
descendant - yes, it will get the three pixels! Specifying units
is a poisoned bequest in that it sets in stone gaps that are only
appropriate to the ancestor.
I have something on this that illustrates the issue that you may
find useful if the above is too obscure.
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http://dorayme.netweaver.com.au/alt/line-height_demo.html>