<html xmlns="http://www.w3.org/1999/xhtml"> <head> <bindings xmlns="http://www.mozilla.org/xbl" xmlns:xhtml="http://www.w3.org/1999/xhtml"> <binding id="a"> <content> <xhtml:div class="aparent"> <xhtml:div class="a"> <children> <xhtml:div class="b"> TEXT </xhtml:div> </children> </xhtml:div> </xhtml:div> </content> </binding> </bindings> <style> @namespace xbl "http://www.mozilla.org/xbl"; .a > .b { color: green; } .a > xbl|children > .b { text-decoration: underline; } .a .b { text-transform: lowercase; } .aparent > * > .b { background: yellow; } /* Inverse cases. */ .a > * > xbl|children > .b { color: red !important; } </style> </head> <body> <div style="-moz-binding: url(#a);" /> </body> </html>