.w1200{ width:1200px; margin:0px auto; overflow:hidden;}	
.top{ background-color: #074e9c; background-image:url("../images/py_01.jpg"); background-position: center;  background-repeat:no-repeat; height: 500px; overflow: hidden;}
.nav{ background-color:#003387; height: 70px; border-bottom: 6px solid #aeadad;margin-bottom: 30px;}
.nav li{ float:left; font-size: 24px; line-height: 70px; color: #fff; width: 200px; text-align: center;}
.nav li a{ color:#fff;font-size: 24px;}
.nav li a:hover{ background-color:#001f51;padding: 20px 30px;}