iv span { display: inline; margin: -1em 0 0 0; border: solid 1em transparent; border-style: none solid; float: right; background: black; height: 1em; }
   .smile div div span em { float: inherit; border-top: solid yellow 1em; border-bottom: solid black 1em; } /* zero-height block; width comes from (zero-height) child. */
   .smile div div span em strong { width: 6em; display: block; margin-bottom: -1em; /* should have no effect, since parent has top&bottom borders, so this margin doesn't collapse */ }

   /