@namespace a url(http://www.example.org/a);
@namespace b url(http://www.example.org/b);
@namespace html url(http://www.w3.org/1999/xhtml);
*|p, *|q, *|r, *|s { display : block ; margin-bottom : 1em }
*|p, *|r { background-color : red }
*|*[a|foo|="bar"], *|*[html|lang|="en"] { background-color : lime }