class="button-bar">
      <button data-color="red">Red</button>
      <button data-color="yellow">Yellow</button>
      <button data-color="green">Green</button>
      <button data-color="purple">Purple</button>
    </div>

  <script>

  const buttonBar = document.querySelector('.button-bar');

  // Add your code here

  </script>
  </body>
</html>
