.card-container {
    perspective: 1000px;
    -webkit-perspective: 1000px;
    -moz-perspective: 1000px;
    transform-style: preserve-3d;
}
.card-container.flipped .front {
    transform: rotateY(180deg);
}
.card-container.flipped .back {
    transform: rotateY(360deg);
}
.card-container, .front, .back {
    width: 100%;
    height: 250px;
}
.flipper {
    transform-style: preserve-3d;
    position: relative;
}
.front, .back {
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    -moz-backface-visibility: hidden;
    transition: 3s;
    transform-style: preserve-3d;
    position: absolute;
    top: 0;
    left: 0;
}
.front {
    z-index: 2;
    transform: rotateY(0deg);
    -webkit-transform: rotateY(0deg);
    -ms-transform: rotateY(0deg);
    -moz-transform: rotateY(0deg);
}
.back {
    transform: rotateY(180deg);
    -webkit-transform: rotateY(180deg);
    -ms-transform: rotateY(180deg);
    -moz-transform: rotateY(180deg);
}