This seems like a decent approach. Your vocabulary is difficult to follow. Widows and orphans are typographical terms (and CSS is largely concerned with typographical info) and you seem to be using them as tree terms (what's there, what's not, when it's used). Real widows and orphans are still nigh impossible to deal with in HTML b/c browsers, even with specific layouts, aren't pixel perfect and certainly don't implement drawing in predictable ways from one to another; and pagination isn't really an issue unless the page is going to the printer.
One perl note (other monks are better qualified to find these if there are more):
$style =~ /\.([^:]*)/ ;
Should probably be something more like:
$style =~ /\.((?:[^:]|[-\w])+)/;
Otherwise "." or ".#!$@" are style names that could be picked up. And even the way I've got it is too simplistic, it could pick up invalid names. The inplace modification of the $_ is probably more confusing than it needs to be.
Good luck. If you get a final version you like, you might post it to the code catacombs.