.header .logo img{width: 4.56rem;height: auto;}
.a1{display: none;}
.nytop .posi:before{content: none;}
@media screen and (max-width: 999px) {

.nysubnav ul li{width: 25%;float:left;}

}

@media screen and (max-width: 768px) {

.nysubnav ul li{width: 30%;}

}

@media screen and (max-width: 500px) {

.nysubnav ul li{width: 50%;}

}