#f1_container {
    position: relative;
    margin: 10px auto;
    width: 450px;
    height: 281px;
    z-index: 1;
}

#f1_container {
    perspective: 1000;
}

#f1_card {
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: all 1.0s linear;
}

#f1_container:hover #f1_card {
    transform: rotateY(180deg);
    box-shadow: -5px 5px 5px #aaa;
}

.face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
}

.face.back {
    display: block;
    transform: rotateY(180deg);
    box-sizing: border-box;
    padding: 10px;
    color: white;
    text-align: center;
    background-color: #aaa;
}