.banner {
    margin: 20px auto;
    width: 1200px;
    overflow: hidden;
}
.large_box {
    margin: 0 auto;
    width: 1170px;
    height: 830px;
    overflow: hidden;
    text-align: center;
}
.large_box img {
    margin: 0 auto;
    width: 50%;
    height: auto;
}
.small_box {
    width: 1200px;
    height: 215px;
    overflow: hidden;
}
.small_list {
    position: relative;
    float: left;
    width: 1120px;
    height: 215px;
    overflow: hidden;
}
.small_list ul {
    height: 215px;
    overflow: hidden;
}
.small_list ul li {
    position: relative;
    float: left;
    margin: 10px 10px 10px 0;
    width: 160px;
    height: 160px;
}
.small_list ul li img {
    display: block;
    margin: 10px auto;
    width: 140px;
    height: 140px;
}
.small_list ul li.on {
    border: 2px solid rgba(0, 153, 51, 1);
}
.btn {
    display: block;
    width: 25px;
    height: 48px;
    margin-top: 70px;
    background-position: center center;
    cursor: pointer;
}
.btn:hover {
    border: 1px solid rgba(0, 153, 51, 1);
}
.left_btn {
    float: left;
    margin-right: 12px;
    background: url(../images/prevBtn.png) no-repeat;
}
.right_btn {
    float: right;
    background: url(../images/nextBtn.png) no-repeat;
}
.bun_bg{
    text-align: center;
    margin-top: 10px;
}