body {font-family: Arial, Helvetica, sans-serif;}
.flip-box-back {background-color: #FFFF00; color: #000000; transform: rotateY(180deg);}
.flip-box-front {background-color: #FFFFFF; color: #000000;}
.flip-box-front, .flip-box-back {-webkit-backface-visibility: hidden; backface-visibility: hidden;}
.flip-box-inner {text-align: center; transition: transform 0.8s; transform-style: preserve-3d;}
.well {background-color: transparent;}
.well:hover .flip-box-inner {transform: rotateY(180deg);}