[Mediawiki-l] Extrange "user" CSS style sheet

[Javier Valcarce García]

Hi all,

How can I edit this style sheet generated by MediaWiki?
http://hklab.net/w/index.php?title=-&action=raw&gen=css&maxage=18000&smaxage=0

It shows:
/* generated user stylesheet */
a.new, #quickbar a.new { color: #CC2200; }
.editsection { display: none; }

If I replace "raw" by "edit" in the URL, MediaWiki shows me a blank page
¿?

Sorry for my poor english. Regards.
Javi