Can't scroll https://drafts.csswg.org/ from the keyboard

Load https://drafts.csswg.org/
Press the spacebar, or the ‘page down’ or ‘end’ key.
Expected result: page scrolls down
Actual result: nothing happens :-(

Put a sad face, curse a little, try to find the rodent…

(Safari 9, Firefox 43 – OS X 10.11)

Regards,
Philippe
--
Philippe Wittenbergh
http://l-c-n.com/