
.clearfloat:after{
    display:block;
    clear:both;
    content:"";
    visibility:hidden;
    height:0
}
.clearfloat{
    zoom:1
}
.mt20{
    margin-top: 20px;
}
.mt40{
    margin-top: 40px;
}
.mr30{
    margin-right: 30px;
}
.main{
    width: 1200px;
    margin: 50px auto;
    color: rgb(100,100,100);
    text-align: center;
}
.top_head{
    margin-right:60px;
}
.main>.top{
    /*text-align: center;*/
    margin:130px 0 50px;
}
.main>.top>.top_head h1{
    font-size: 26px;
    font-weight: normal;
    color: #323232;
}
.main>.top>.top_head p{
    font-size: 16px;
    color: #636363;
}
.main>.top>.item{
    width: 380px;
    float: left;
    margin-top: 50px;
}
.main>.top>.item>h2{
    font-size: 20px;
    color: rgb(50, 50, 50);
    font-weight: normal;
}
.main>.top>.item>p{ 
    font-size: 12px;
    line-height: 20px;
    color: #646464;
}
.main>.center{
    margin-bottom:50px;
}
.main>.center>.center_item{
    box-sizing: border-box;
    width: 380px;
    height: 450px;
    float: left;
    border: 1px solid #F5F5F5;
    margin-top: 30px;
}
.main>.center>.center_item>img{
    width: 100%;
}
.main>.center>.center_item>h3{
    font-size: 24px;
    font-weight: normal;
    margin-top: 30px;
    color: #636363;
}
.main>.center>.center_item>p{
    font-size: 16px;
    line-height: 26px;
}
.main>.center>.center_item p:first-of-type {
    margin-top: 40px;
    color: #7F7F7F;
}

/*手机样式*/
@media screen and (max-width: 720px){
    .main{
        width: 100%;
        margin:0 auto;
        padding-top: 10px;
    }
    .top_head{
        margin:0; 
    }
    .main>.top{
        margin:0;
    }
    .main>.top>.item{
        width:33.3%;
    }
    .main>.center>.center_item{
        width: 100%;
        border: none;
    }
}