header {
        border-bottom: 1px solid #ccc;
        background: #fff !important;
    }
    .main {
        width: 1200px;
        overflow: hidden;
        margin: 0 auto;
    }
    .logo img {
    margin-top: 12px;
    max-height: 36px;
}

.ar_nav {
    /* width: 900px; */
    height: 49px;
    overflow: hidden;
}
.nav_wrap {
    position: relative;
    height: 52px;
}
.nav_item {
    float: left;
}
.nav_item span a {
    padding: 0;
    margin-left: 30px;
    color: #333;
    height: 48px;
    line-height: 48px;
    font-size: 14px;
    position: relative;
}