.flip {
    position: relative;
    -webkit-perspective: 1000;
    -moz-perspective: 1000;
    -ms-perspective: 1000;
    -o-perspective: 1000;
    perspective: 1000;
}
.flip .flip-front, .flip .flip-back {
    position: absolute;
    top: 0;
    left: 0;
    -webkit-transform-style: preserve-3d;
    -moz-transform-style: preserve-3d;
    -ms-transform-style: preserve-3d;
    -o-transform-style: preserve-3d;
    transform-style: preserve-3d;
    -webkit-backface-visibility: hidden;
    -moz-backface-visibility: hidden;
    -ms-backface-visibility: hidden;
    -o-backface-visibility: hidden;
    backface-visibility: hidden;
    -webkit-transition: 0.75s;
    -moz-transition: 0.75s;
    -o-transition: 0.75s;
    transition: 0.75s;
}