title: Web Animation, how to animate the background rgba color
body: <p>I want to animate the background color in rgba for a modal so it fades in. I cant use opacity as the div inside the modal I dont want to be transparent. I cant use Jquery but I am using React.</p>
  
  <p>I'm not getting an error by the below does not work</p>
  
  <pre><code>const modal = document.getElementById('modal');
  modal.animate(
  [
    {backgroundColor: 'rgba(255, 0, 0, 0)'}, 
    {backgroundColor: 'rgba(255, 0, 0, 0.8)'}
  ], 
    {duration: 200, easing: 'ease-in-out', fill: 'forwards'}
  );
  </code></pre>