/* Source: http://www.w3.org/Style/CSS/Test/CSS3/Selectors/current/html/tests/css3-modsel-155b.html */p{background:lime;}.two\words{background:red;}/* the "." and "~=" forms match on a space separated list of words. In such a list, a word containing a space can never match, since it would by definition be two words. */