.wrap {
    width: 1e3px;
    margin: 20px auto
}

.poster-main {
    width: 640px;
    height: 270px;
    position: relative
}

.poster-main .poster-btn {
    width: 100px;
    height: 270px;
    position: absolute;
    top: 0;
    cursor: pointer
}

.poster-main .poster-prev-btn {
    left: 0;
    background: url(./1.png) no-repeat;
    background-position: left center
}

.poster-main .poster-next-btn {
    right: 0;
    background: url(./2.png) no-repeat;
    background-position: right center
}

.poster-main .poster-list .list-item {
    position: absolute;
    top: 0;
    left: 0
}

.list-item,.list-item img {
    display: block;
    width: 100%;
    height: 100%;
    border: 0
}