*, *:before, *:after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  
  .demo {
    display: flex;
    width: 100vw;
    height: 100vh;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    background: linear-gradient(60deg, #5B5893, #2c2a49);
  }
  .demo__gallery {
    width: 688px;
    height: 460px;
    padding: 2px;
    flex-shrink: 0;
    background: #eee;
    perspective: 700px;
    border-radius: 5px;
  }
  .demo__placeholder {
    width: 110px;
    height: 110px;
    margin: 2px;
    float: left;
    background-color: lightslategrey;
    border-radius: 5px;
  }
  .demo__part {
    position: relative;
    float: left;
    width: 110px;
    height: 110px;
    margin: 2px;
    transform: rotateY(180deg);
    transform-style: preserve-3d;
    transition: all 0.3s ease-in-out;
  }
  .demo__part:hover .demo__part-front {
    box-shadow: 0 0 10px black;
    transform: scale(0.96);
  }
  .demo__part:hover .demo__part-front:after {
    opacity: 0;
  }
  .demo__part-front, .demo__part-back {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    -webkit-backface-visibility: hidden;
            backface-visibility: hidden;
    border-radius: 5px;
    cursor: pointer;
  }
  .demo__part-front {
    background-color: lightslategrey;
    background-size: cover;
    background-position: center;
    transform: rotateX(0deg);
    transition: all 0.2s ease;
  }
  .demo__part-front:after {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: black;
    content: "";
    opacity: 0.5;
    transition: all 0.2s ease;
  }
  .demo__part-back {
    transform: rotateY(180deg) rotateX(0deg);
  }
  .demo__part-back-inner {
    width: 680px;
    height: 452px;
    background-image: url(http://kirillkiyutin.com/img/nyc/nyc1.jpg);
    background-size: cover;
    background-position: center;
    -webkit-backface-visibility: hidden;
            backface-visibility: hidden;
  }
  .demo__help {
    margin-bottom: 7px;
    font-size: 30px;
    font-family: "Yanone Kaffeesatz", sans-serif;
    color: white;
  }
  .demo__help a {
    color: white;
  }
  .demo__help a:hover {
    color: #E39999;
  }
  
  .demo__part-1-1 .demo__part-back-inner {
    transform: translate(0px, 0px);
  }
  
  .demo__part-1-2 .demo__part-back-inner {
    transform: translate(-114px, 0px);
  }
  
  .demo__part-1-3 .demo__part-back-inner {
    transform: translate(-228px, 0px);
  }
  
  .demo__part-1-4 .demo__part-back-inner {
    transform: translate(-342px, 0px);
  }
  
  .demo__part-1-5 .demo__part-back-inner {
    transform: translate(-456px, 0px);
  }
  
  .demo__part-1-6 .demo__part-back-inner {
    transform: translate(-570px, 0px);
  }
  
  .demo__part-2-1 .demo__part-back-inner {
    transform: translate(0px, -114px);
  }
  
  .demo__part-2-2 .demo__part-back-inner {
    transform: translate(-114px, -114px);
  }
  
  .demo__part-2-3 .demo__part-back-inner {
    transform: translate(-228px, -114px);
  }
  
  .demo__part-2-4 .demo__part-back-inner {
    transform: translate(-342px, -114px);
  }
  
  .demo__part-2-5 .demo__part-back-inner {
    transform: translate(-456px, -114px);
  }
  
  .demo__part-2-6 .demo__part-back-inner {
    transform: translate(-570px, -114px);
  }
  
  .demo__part-3-1 .demo__part-back-inner {
    transform: translate(0px, -228px);
  }
  
  .demo__part-3-2 .demo__part-back-inner {
    transform: translate(-114px, -228px);
  }
  
  .demo__part-3-3 .demo__part-back-inner {
    transform: translate(-228px, -228px);
  }
  
  .demo__part-3-4 .demo__part-back-inner {
    transform: translate(-342px, -228px);
  }
  
  .demo__part-3-5 .demo__part-back-inner {
    transform: translate(-456px, -228px);
  }
  
  .demo__part-3-6 .demo__part-back-inner {
    transform: translate(-570px, -228px);
  }
  
  .demo__part-4-1 .demo__part-back-inner {
    transform: translate(0px, -342px);
  }
  
  .demo__part-4-2 .demo__part-back-inner {
    transform: translate(-114px, -342px);
  }
  
  .demo__part-4-3 .demo__part-back-inner {
    transform: translate(-228px, -342px);
  }
  
  .demo__part-4-4 .demo__part-back-inner {
    transform: translate(-342px, -342px);
  }
  
  .demo__part-4-5 .demo__part-back-inner {
    transform: translate(-456px, -342px);
  }
  
  .demo__part-4-6 .demo__part-back-inner {
    transform: translate(-570px, -342px);
  }
  
  .show-front {
    transform: none;
  }