What should we do here

what should we do here please say

Your code so far

:root {
  --red-color: red;
.red-box {
  background: var(--red-color,);
  height: 200px;

<div class="black-box"></div>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36.

Challenge: Improve Compatibility with Browser Fallbacks

Link to the challenge:

the figure disappeared because there is no more an element with class red-box, please reset your code

the thing to do here is to add a background declaration to make the element red, even when the browser don’t know how to use variables, so you need to add a background declaration to make it red that doesn’t use a variable