#nav li {margin: 0; padding: 0; list-style: none; display: inline;}
#nav a { float:left; padding: 113px 0 0 0; overflow: hidden; height: 0px;}
#nav a:hover { background-position: 0 -113px;}
#nav1 a {width:120px;background:url(../images/nav_home.jpg) top left no-repeat;}
#nav2 a {width:120px;background:url(../images/nav_product.jpg) top left no-repeat;}
#nav3 a {width:120px;background:url(../images/nav_company.jpg) top left no-repeat;}
#nav4 a {width:120px;background:url(../images/nav_contact.jpg) top left no-repeat;}