<div class="container">
  <p>Change the values of the <code>border</code> property to see how the border changes.</p>
  <div class="element">
    <p>
      I have a 5px solid green border.
    </p>
  </div>
</div>
body {
  background-color: #F7FAFC;
  color: #555;
  font-size: 1.1em;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

.container {
  margin: 40px auto 0;
  max-width: 700px;
}

.element {
  padding: 20px;
  height: 300px;
  background-color: white;
  border: 5px solid #009966;
}