.poster-main {
  width: 800px;
  height: 385px;
  position: relative;
  margin: 0 auto;
  margin-top:35px;
}
.poster-main a, .poster-main img { display: block; }
.poster-main .poster-list {
  width: 1000px;
  height: 500px;
}
.poster-main img{
  border:5px solid #fff;
  box-shadow: 4px 4px 4px #ccc;
}
.poster-main .poster-list .poster-item {
  width: 200px;
  height: 500px;
  position: absolute;
  left: 0;
  top: 0;
}
.poster-main .poster-btn {
  position: absolute;
  top: 0;
  z-index: 10;
  cursor: pointer;
}

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

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