The FAQ page's method for adding borders to tables doesn't work for me

This recipe has no effect on the tables I have imported from Mediawiki:

Thought it might be from caching of the CSS in the browser, but a fresh browser makes no difference. My guess is the CSS coding has changed some of the labels used since the FAQ was written. But I don’t know how to directly view the stock XWiki CSS to work that out. Is there a way to dump the generated default CSS to a file for examination?