I found that an element can have more than one class.
Like, when all paragraphs are indented and I want to remove indent from first paragraph then it's enough to add "first" to the existing p class
Code:
<p class="calibre1 first">
and
Code:
.first {text-indent:0}
to the css.
Result looks the same if I copy the normal paragraph class, change text-indent to 0 (and it's name) and then change p class in every first paragraph to the new name.
Or if I want one p to be exactly like others, only little bit smaller. Why should I create new class with only one difference from previous?
But is it safe to use, can most/all readers cope with it? If yes, then why is it so seldom used? Or is there some other reason why I see (mostly) that every h or p has only one class; maybe it won't convert well?