title: Why 3 font-size declaration
body: <p>I've downloaded a standard theme whose main file normalize.css contains these declarations in the very beginning. <strong>I'm confused why three font-sizes</strong>:</p>
  
  <pre><code>html {
    font-family: Verdana, Tahoma, "DejaVu Sans", sans-serif; /* 1 */
  
    /* Delete all but one of the following font-size declarations: */
  
    /* Use a 12px base font size. 16px x 75% = 12px */
    font-size: 75%; /* 3 */
    /* Use a 14px base font size. 16px x .875 = 14px */
    font-size: 87.5%; /* 3 */
    /* Use a 16px base font size. */
    font-size: 100%; /* 3 */
  
    -ms-text-size-adjust: 100%;     /* 2 */
    -webkit-text-size-adjust: 100%; /* 2 */
  
    /* Establish a vertical rhythm. */
    line-height: 1.5em;
  }
  </code></pre>
  
  <p>All I want is to use base font-size of 14px.</p>