Improve Compatibility with Browser Fallbacks.,,

Tell us what’s happening:
" Your .red-box rule should include a fallback with the background set to red immediately before the existing background declaration."
Is this what it is wanting?
Can someone explain how this is done

Your code so far

  :root {
    --red-color: red;
  .red-box {
    background: var(--red-color);
    background: var(--red-color);
    height: 200px;
<div class="red-box"></div>

Your browser information:

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36.

Link to the challenge:

your first style inside your .red-box should just be


That way when your style with variable fails, it will resort back to the previous line.