.aboutbanner{
    width: 100%;
    height: 500px;
    background: url(../images/aboutbanner.jpg);
    background-size: 100%;
  }
.switch{
    width: 100%;
    height: 80px;
    border-top: 1px solid #bdbdbd;
    border-bottom: 1px solid #bdbdbd;
    margin-top: 48px;
}
.switchthree{
    width: 899px;
    height: 100%;
    margin: auto;
}
.jianjie{
    width: 50%;
    height: 100%;
    border-left: 1px solid #bdbdbd;
    
    float: left;
}
.wenhua{
    width: 50%;
    height: 100%;
    border-left: 1px solid #bdbdbd;
    border-right: 1px solid #bdbdbd;
    border-bottom: 4px solid #313131;
    float: left;
}
h2{
    color: #313131;
    font-size: 22px;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
    line-height: 80px;
}
.light{
    width: 100%;
    height: 150px;
    background-color: #f6f6f6;
}
.weight{
    width: 100%;
    height: 150px;
    background-color: #e4e4e4;
}

.btleft{
    width: 20%;
    height: 100%;
    text-align: center;
    float: left;
}
.btleft span{
    color: #313131;
    font-size: 24px;
    font-family: Arial, Helvetica, sans-serif;
    line-height: 150px;
}
.whright{
    width: 80%;
    height: 100%;
    float: left;
}
.row-1{
    margin-top: 46px;
}
.row-1 span{
    color: #313131;
    font-size: 24px;
    font-family: Arial, Helvetica, sans-serif;
    text-transform:uppercase;
}