I want to use an Opera's proprietary property:
This Opera CSS linking extensions makes clickable an element with a "cite" attribute (usually "q" ou "blockquote"). (source)
Sadly, the CSS Editor in WordPress 3.4.2. with the TwentyTwelve theme discards it. I could create a child theme, but I'd rather avoid it and stick with the CSS editor. Fixing this seems a cleaner approach to me.