Support for CSS (Stylesheets) in Netscape 4.7x is spotty at best. It just is too old to fully support the latest technologies.
I know that 4.7 doesn't accept the "blockquote" class in threads (which is used for the quote box), and some users complain that the menu bar comes and goes.
The message composition window also doesn't wrap and 4.7 users usually have to hit enter at the end of each line.
