html, body {
    width: 100%;
    height: 100%;
    margin: 0px;
    padding: 0px;
}
body {
    position: fixed;
    -webkit-transform-style: preserve-3d;
    transform-style: preserve-3d;
    -webkit-font-smoothing: antialiased;
    -webkit-tap-highlight-color: transparent;
    -webkit-perspective: 0;
    perspective: none;
    overflow: hidden;
    background: #333;
}
board {
    background-color: white;
}
piece {
    cursor: pointer;;
    background-repeat: no-repeat;
    background-color: white;
    position: relative;
    -webkit-transition: box-shadow 100ms;
    transition: box-shadow 100ms;
}
piece:hover {
    z-index: 2;
    box-shadow: 0 0 40px 0 rgba(0, 0, 0, 0.8);
}
piece.in-motion {
    z-index: 2;
    box-shadow: 0 0 100px 0 rgba(0, 0, 0, 0.8);
}