/**
 * Demo
 */
.box {
  cursor: pointer;
  margin:20px auto;
}
.box .front,
.box .back {
  padding: 1em 1.1em;
  text-align: center;
  font-size: 2em;
  color: white;
}
.box .front {
  background: url("https://unsplash.it/400/350?image=845");
}
.box .back {
  background: url("https://unsplash.it/400/350?image=745");
}
body { background-color:#434A53; color:#fff;}
.container { margin:150px auto; max-width:400px;}