#nav_menu {
    font-family:Verdana, Arial, Helvetica, sans-serif;
    font-size:12px;
    color:#FFFFFF;
    font-weight:bold;
   list-style:none;
   margin:0; padding:0;
}
#nav_menu li{
   float:left;
   list-style:none;
}
#nav_menu img{
    border:none;
    display:block;
}

/* menus */
#nav_menu .submenu { 
    position:absolute;
    display:none;
}

#nav_menu .submenu, #nav_menu .submenu li{
   list-style:none;
   margin:0; padding:0;
}

#nav_menu .submenu li{
   display:block;
   float:none;
}

#nav_menu #over ul{
   background-color:#706284;
   width:200px;
}
#nav_menu #treatment ul{
   background-color:#7CB0AD;
   width:500px;
}
#nav_menu #research ul{
   background-color:#7C8BB0;
   width:400px;
}
#nav_menu #education ul{
   background-color:#8CB07C;
   width:300px;
}
#nav_menu #prevent ul{
   background-color:#A8B07C;
   width:300px;
}

/* links */
#nav_menu ul li a{
   display:block;
   text-decoration:none;
   color:#FFFFFF;
   padding:2px 6px;
   margin:0;
}
#nav_menu #over ul li a:hover{
   background-color:#9689AF;
}
#nav_menu #treatment ul li a:hover{
    background-color:#9DC4C1;
}
#nav_menu #research ul li a:hover{
	background-color:#A5AFC9;
}
#nav_menu #education ul li a:hover{
   background-color:#AECBA2;
}
#nav_menu #prevent ul li a:hover{
   background-color:#C8D09E;
}