.demo .wrapper {
  position: absolute;
  z-index: 2;
  transition: opacity 0.3s;
}

.wrapper i {
  position: absolute;
  -webkit-animation: sdb04 2s infinite;
  animation: sdb04 2s infinite;
  box-sizing: border-box;
}

@-webkit-keyframes sdb04 {
  0% {
    -webkit-transform: translate(-50%, -50%);
  }
  20% {
    -webkit-transform: translate(-50%, 0);
  }
  40% {
    -webkit-transform: translate(-50%, -50%);
  }
}