Basic CSS - Improve Compatibility with Browser Fallbacks

Tell us what’s happening:

I am little bit of confused here can anyone explain me this what we have to do here

Your code so far

<style>
  :root {
    --red-color: red;
  }
  .red-box {

    background: red,var(--red-color);
    height: 200px;
    width:200px;
  }
</style>
<div class="red-box"></div>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Challenge Information:

Basic CSS - Improve Compatibility with Browser Fallbacks

instead of doing this, add another background just above this line, and use the value red

thanks alot ilenia​:heart::heart::heart::heart::heart::heart: