title: Edit line thickness of CSS 'underline' attribute
body: <p>Since you can underline any text in CSS like so:</p>
  <pre class="lang-css prettyprint-override"><code>h4 {
    text-decoration: underline;
  }
  </code></pre>
  <p>How can you also then edit the 'line' that is drawn, the color you get on the line is easily specified as <code>color: red</code> but how does one edit the height of the line, i.e. the thickness?</p>