.myrow_box .m{
    display: none;
}
.contactus.m{
    display:none
}
@media screen and (max-width:768px){
    .myrow_box .m{
        display: block;
    }
   .product_title{
      height: 80px;
   } 
   .product_title h4{
    margin: 0 0 13px 0;
   }
   .product_fenlei ul{
    padding: 1px 0;
   }
   .product_fenlei ul li{
    padding: 12px 10px;
    float: left;
    width: 50%;
    font-size: 14px;
   }
   .clear:after{
    content: "";
    width: 0;
    height: 0;
    display: block;
    clear: both
   }
   .contactus.pc{
    display: none;
   }
   .product_title{
    padding-left: 13px;
   }
   .contactus.m{
    display: block;
   }
   .myrow_box .pc{
    display: none;
   }
}