http://www.opro.org/index.php
CSS in question at http://www.opro.org/default.css and
http://www.opro.org/imported.css
This is a PHP experiment served as application/xhtml+xml when possible.
The document is otherwise identical to http://www.opro.org/index.html
which is served as text/html.
Issue: In Mozilla 1.6, on the .php (xml+xhtml) page the body element does
not extend to the bottom of the viewport - note the background color. In
the .html (text/html) version, it does.
Stumped.