Help me out...stucked here

Tell us what’s happening:

Your code so far

  :root {
  --red-color: red;
.red-box {
  background: var(--red-color);
  width: 100px;
  height: 100px;
.red-box {
  background: var(--red-color);
  width: 150px;
  height: 200px;

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36.

Challenge: Improve Compatibility with Browser Fallbacks

Link to the challenge:


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From the code you have, I can see you have deleted necessary code. Please hit the reset button on the challenge, and start again.

thank you for the reply. i have got the solution myself. thank you very much for offering a help