title: CSS transition background gradient
body: <p>I'm trying to get a CSS transition to fade in a background gradient.</p>
  
  <p>I had the transition working when it was just flat colours, but now that I've changed it to a radial gradient it just appears instantly. I think it might also be something to do with the fact I'm using a semi-transparent colour as one of the colour values.</p>
  
  <pre><code>.cta-01 .cta a:hover {
      background-image:
          radial-gradient(
            circle,
            rgba(0, 0, 0, .75),
            rgba(0, 0, 0, 1)
          );
  
      -webkit-transition: background-image 250ms linear;
      -moz-transition: background-image 250ms linear;
      -o-transition: background-image 250ms linear;
      -ms-transition: background-image 250ms linear;
      transition: background-image 250ms linear;
  }
  </code></pre>
  
  <p>Can anyone see what I'm doing wrong?</p>