.pop {
    visibility: hidden;
}

.pop--show {
    visibility: visible;
}

.pop__mask {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 10;
    background: rgba(0, 0, 0, 0.4);
    display: none;
}

.pop__mask--hide {
    background: 0 0;
}

.pop__container {
    position: fixed;
    left: 50%;
    top: 50%;
    transform: translate3d(-50%, -50%, 0);
    transform-origin: center;
    transition: all 0.4s ease;
    -moz-transition: all 0.4s ease; /* Firefox 4 */
    -webkit-transition: all 0.4s ease; /* Safari 和 Chrome */
    -o-transition: all 0.4s ease;; /* Opera */
    z-index: 11;
    opacity: 0;
    background-color:transparent;
}

.pop--show .pop__container {
    opacity: 1;
}

.pop--show .pop__mask {
    display: block;
}

.pop--left .pop__container {
    left: 0;
    top: 50%;
    transform: translate3d(-100%, -50%, 0);
}

.pop--show.pop--left .pop__container {
    transform: translate3d(0, -50%, 0);
}

.pop--right .pop__container {
    right: 0;
    top: 50%;
    left: auto;
    transform: translate3d(100%, -50%, 0);
}

.pop--show.pop--right .pop__container {
    transform: translate3d(0, -50%, 0);
}

.pop--bottom .pop__container {
    top: auto;
    left: 50%;
    bottom: 0;
    transform: translate3d(-50%, 100%, 0);
}

.pop--show.pop--bottom .pop__container {
    transform: translate3d(-50%, 0, 0);
}

.pop--top .pop__container {
    top: 0;
    left: 50%;
    transform: translate3d(-50%, -100%, 0);
}

.pop--show.pop--top .pop__container {
    transform: translate3d(-50%, 0, 0);
}