html,
body {
    margin: 0;
    height: 100%;
}

body {
    background-color: #efefef;
}

body.hide-overflow {
    overflow: hidden;
}


/* helpers */

.t {
    position: fixed;
    display: table;
    width: 100%;
    height: 100%;
}

.tc {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
}

.rel {
    position: relative;
}


/* book */

.book {
    overflow: hidden;
    margin: 0 auto;
    width: 100%;
    height: 100%;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.book .page {
    width: 100%;
    height: 100%;
    background-color: #efefef;
}

.book .page img {
    max-width: 100%;
}


#popCloseBtn {
    position: absolute;
    left: 90%;
    bottom: 100%;
}

#goIndex {
    position: absolute;
    background: url(../img/home.png) no-repeat center center;
    background-size: contain;
    top: 3%;
    left: 4%;
    width: 7%;
    height: 5%;
    z-index: 10;
}