Create Movement Using CSS Animation error

Tell us what’s happening:
I have type left offset correctly but the browser doesn’t accept this. And so I am unable to go ahead of the code.

Your code so far

  div {
    height: 40px;
    width: 70%;
    background: black;
    margin: 50px auto;
    border-radius: 5px;
    position: relative;

#rect {
  animation-name: rainbow;
  animation-duration: 4s;

@keyframes rainbow {
  0% {
    background-color: blue;
    top: 0px;
    left: 0px;
  50% {
    background-color: green;
    top: 25px;
    left: 25px;

  100% {
    background-color: yellow;
    top: 50px;
    left: -25px;

<div id="rect"></div>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36.

Link to the challenge:

You have altered the top property at 50% and 100%, do not change the existing code. Put back the old values of top, i guess its 50px for 50% and 0px for 100%