title: Margin and padding using em
body: <p>When 1em is applied to an element, it takes the default value of the browser (usually, 16px) or the font-size value of its parent, right?. But I noticed that if I use something like <code>margin-top: 1em</code> in a <code>h1</code> element (without using a reset stylesheet, and therefore, h1 is set to <code>font-size: 32px</code>), then 1em is equal to <code>32px</code>, even if its parent element is set to <code>font-size: 16px</code>.</p>
  
  <p>However, using something like font-size: 100%; solves the discrepancy.</p>
  
  <p>What am I missing?</p>