.web_nav{display:none}
#nav dl{display:none}
@media(max-width:767px){
#nav dl{display:block}
#nav dl a {
    width: 25%;
    float: left;
    text-align: center;
    color: #fff;
    display: inline-block;
    line-height: 45px;
    border-bottom: 1px solid #dfdfdf;
    border-right: 1px solid #dfdfdf;
    box-sizing: border-box;
}
}