title: What is the "root element" for rem?
body: <p>W3 <a href="http://www.w3.org/TR/css3-values/#rem" rel="noreferrer">says</a>:</p>
  
  <blockquote>
    <p>Equal to the computed value of font-size on the root element. When specified on the font-size property of the root element, the rem units refer to the property’s initial value.</p>
  </blockquote>
  
  <p>What is this "root element" referring to? <code>&lt;html&gt;</code>? <code>&lt;body&gt;</code>?</p>