title: Firefox includes border in height of <hr> whilst chrome does not
body: <p>I'm trying to style a border so that it consist of a</p>
  
  <p>1px green line below a 1px white line </p>
  
  <pre><code>hr{
      height: 1px;
      border: 0;
      background-color: #89a889;
      border-bottom: 1px solid #fafafa;
  }
  </code></pre>
  
  <p>this works in webkit, but firefox seems to include the border in the total height of the line. This makes the bottom border cover the green line. Whan can I do about this?</p>