rendering of a pre tag block inside a MediaWiki page should be the same rendering as MediaWiki

Inside a xwiki page with MediaWiki syntax, the rendering of a text block with tag 'pre' is not in monospace font. 

Expected rendering (ie monospace and grey background) : see pre tag (preformatted text) in the MediaWiki doc : https://www.mediawiki.org/wiki/Help:Formatting

So the css config should be :

font-family: monospace !important;

instead of

font-family: inherit;

and the background should be grey.