.animation-container {
  padding: 50px;
}
.animating-div {
  background-color: #4C5FD9;
  height: 100px;
  left: 0;
  position: relative;
  top: 0;
  width: 100px;
}
.animating-div.is-animating {
  left: 100px;
  -webkit-transition: left 1s ease;
  transition: left 1s ease;
}
.animating-div.custom-animation {
  opacity: 0;
  top: 100px;
  -webkit-animation: custom-animation 1s;
  -moz-animation:    custom-animation 1s;
  -o-animation:      custom-animation 1s;
  animation:         custom-animation 1s;
}
.animating-div.returning-animation {
  left: 0;
  opacity: 1;
  top: 0;
  -webkit-animation: return-animation .5s;
  -moz-animation:    return-animation .5s;
  -o-animation:      return-animation .5s;
  animation:         return-animation .5s;
}

@-webkit-keyframes custom-animation {
  0%   {
    opacity: 1;
    top: 0;
  }
  100% {
    opacity: 0;
    top: 100px;
  }
}
@-moz-keyframes custom-animation {
  0%   {
    opacity: 1;
    top: 0;
  }
  100% {
    opacity: 0;
    top: 100px;
  }
}
@-o-keyframes custom-animation {
  0%   {
    opacity: 1;
    top: 0;
  }
  100% {
    opacity: 0;
    top: 100px;
  }
}
@keyframes custom-animation {
  0%   {
    opacity: 1;
    top: 0;
  }
  100% {
    opacity: 0;
    top: 100px;
  }
}

@-webkit-keyframes return-animation {
  0%   {
    left: 100px;
    opacity: 0;
    top: 100px;
  }
  100% {
    left: 0;
    opacity: 1;
    top: 0;
  }
}
@-moz-keyframes return-animation {
  0%   {
    left: 100px;
    opacity: 0;
    top: 100px;
  }
  100% {
    left: 0;
    opacity: 1;
    top: 0;
  }
}
@-o-keyframes return-animation {
  0%   {
    left: 100px;
    opacity: 0;
    top: 100px;
  }
  100% {
    left: 0;
    opacity: 1;
    top: 0;
  }
}
@keyframes return-animation {
  0%   {
    left: 100px;
    opacity: 0;
    top: 100px;
  }
  100% {
    left: 0;
    opacity: 1;
    top: 0;
  }
}