<!DOCTYPE html>
<style>
html { background: red; }
html:nth-child(1):nth-last-child(1):nth-of-type(1):nth-last-of-type(1):first-child:last-child:only-child:first-of-type:last-of-type:only-of-type { background: green; }
</style>
<link rel="help" href="https://www.w3.org/TR/css3-selectors/#structural-pseudos">
<link rel="match" href="selector-structural-pseudo-root-ref.html">
<meta name="assert" content="Structural pseudo-classes match the root element, sibling pseudos are based on siblings without needing a parent (Selectors 3 erratum)">