index.css

#app {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-evenly;
  align-items: center;
}

/*Moving background*/
body {
  width: 100vw;
  height: 100vh;
  background: linear-gradient(
    -45deg,
    #f35c9d,
    #ffdf00,
    #ff653a,
    #f35c9d,
    #ffdf00
  );
  background-size: 400% 400%;
  margin: 0;
  overflow: hidden;

  animation: movingBkg 14s linear infinite;
  -moz-animation: movingBkg 14s linear infinite;
  -webkit-animation: movingBkg 14s linear infinite;
}
@keyframes movingBkg {
  0% {
    background-position: top left;
  }
  100% {
    background-position: right bottom;
  }
}
@-moz-keyframes movingBkg {
  0% {
    background-position: top left;
  }
  100% {
    background-position: right bottom;
  }
}
@-webkit-keyframes movingBkg {
  0% {
    background-position: top left;
  }
  100% {
    background-position: right bottom;
  }
}