/* CSS Card Flip */
/* https://jsfiddle.net/james2doyle/qsQun/ */

body {
  background-color: slategrey;
  font-family: Arial, Helvetica, sans-serif;
}
button {
  background-color: darkslategrey;
  color: white;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

@media screen and (min-width: 640px) {
  button, div {
    font-size: 4rem;
  }
}

@media screen and (min-width: 321px) {
  button, div {
    font-size: 2rem;
  }
}

@media screen and (max-width: 320px) {
  button, div {
    font-size: 1.5rem;
  }
}

.container {
  width: device-width;
  height: 260px;
  position: relative;
  border: 1px solid #ccc;
  -webkit-perspective: 800px;
  -moz-perspective: 800px;
  -o-perspective: 800px;
  perspective: 800px;
}
.card {
  width: 100%;
  height: 100%;
  position: absolute;
  -webkit-transition: -webkit-transform 0.25s;
  -moz-transition: -moz-transform 0.25s;
  -o-transition: -o-transform 0.25s;
  transition: transform 0.25s;
  -webkit-transform-style: preserve-3d;
  -moz-transform-style: preserve-3d;
  -o-transform-style: preserve-3d;
  transform-style: preserve-3d;
  -webkit-transform-origin: 50% 50%;
  transform-origin: 50% 50%;
}
.card div {
  display: block;
  height: 100%;
  width: 100%;
  line-height: 260px;
  color: white;
  text-align: center;
  font-weight: bold;
  position: absolute;
  -webkit-backface-visibility: hidden;
  -moz-backface-visibility: hidden;
  -o-backface-visibility: hidden;
  backface-visibility: hidden;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}
.card .front {
  background: rgb(54, 3, 3);
}
.card .back {
  background: rgb(2, 2, 43);
  -webkit-transform: rotateY( 180deg );
  -moz-transform: rotateY( 180deg );
  -o-transform: rotateY( 180deg );
  transform: rotateY( 180deg );
}
.card.flipped {
  -webkit-transform: rotateY( 180deg );
  -moz-transform: rotateY( 180deg );
  -o-transform: rotateY( 180deg );
  transform: rotateY( 180deg );
}