RGBA property not working?

Question

css

Hello. I have a code, but the rgba property does not work in it, what should I do, thanks

<footer>
       <div class = "footer">
 
       </div>
    </footer>

footer {
  width: 100%;
  height: 64px;
  background: rgba(181,181,181,0.2);
  backdrop-filter: blur(5px);
}

Answer 1

You are sure?