style.css

.container {
  position: relative;
  margin: 0 auto;
  height: 270px;
  width: 270px;
}
div > div {
  margin: 5px;
  width: 80px;
  height: 80px;
  opacity: 0.5;
  position: relative;
  float: left;
  z-index: 0;
  background-color: lightgreen;
  -webkit-transform-origin: 0 0;
      -ms-transform-origin: 0 0;
          transform-origin: 0 0;
}
.ghost {
  background-color: transparent;
}
.cover {
  z-index: 10;
  position: absolute;
  opacity: 1;
  width: 100%;
  height: 100%;
  margin: 0;
}
.animate-on-transforms {
  -webkit-transition-property: -webkit-transform,opacity;
          transition-property: transform,opacity;
  -webkit-transition-duration: 350ms;
          transition-duration: 350ms;
  -webkit-transition-timing-function: cubic-bezier(0.68, -0.55, 0.265, 1.55);
          transition-timing-function: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}