#nav {padding:0; margin:0; list-style:none; height:20px; background:#4286B1  repeat-x; z-index:500; font-family:arial, verdana, sans-serif;}
#nav li.top {display:block; float:left; height:20px;}
#nav li a.top_link {display:block; float:left; height:17px; line-height:20px; color:white ; text-decoration:none; font-size:11px; font-weight:bold; padding:0 0 0 0px; cursor:pointer;}
#nav li a.top_link span {float:left; display:block; padding:0 24px 0 10px; height:17px;}
#nav li a.top_link span.down {float:left; display:block; padding:0 24px 0 10px; height:17px;}
<!--  -->
#nav li:hover a.top_link {color:#4286B1;}
#nav li:hover a.top_link span {background:#FFFFFF;}
#nav li:hover a.top_link span.down {background:#ACD6F0;}

/* Default list styling */

#nav li:hover {position:relative; z-index:200;}

#nav li:hover ul.sub
{left:1px; top:20px; background: #ACD6F0; padding:4px; border:1px solid #FFFFFF; white-space:nowrap; width:150px; height:auto; z-index:300;}
#nav li:hover ul.sub li
{display:block; height:20px; position:relative; float:left; width:150px; font-weight:normal;}
#nav li:hover ul.sub li a
{display:block; font-size:11px; height:18px; width:150px; line-height:18px; text-indent:5px; color:navy; text-decoration:none;}
#nav li ul.sub li a.fly
{background:#ACD6F0 no-repeat;}
#nav li:hover ul.sub li a:hover 
{background:#ACD6F0 ; color:#FFFFFF; border-color:#fff;}
#nav li:hover ul.sub li a.fly:hover
{background:#ACD6F0 no-repeat; color:#FFFFFF;}


#nav li:hover li:hover ul,
#nav li:hover li:hover li:hover ul,
#nav li:hover li:hover li:hover li:hover ul,
#nav li:hover li:hover li:hover li:hover li:hover ul
{left:90px; top:-4px; background: #FFFFFF; padding:3px; white-space:nowrap; width:150px; z-index:400; height:auto;}

#nav ul, 
#nav li:hover ul ul,
#nav li:hover li:hover ul ul,
#nav li:hover li:hover li:hover ul ul,
#nav li:hover li:hover li:hover li:hover ul ul
{position:absolute; left:-9999px; top:-9999px; width:0; height:0; margin:0; padding:0; list-style:none;}

#nav li:hover li:hover a.fly,
#nav li:hover li:hover li:hover a.fly,
#nav li:hover li:hover li:hover li:hover a.fly,
#nav li:hover li:hover li:hover li:hover li:hover a.fly
{background: #ACD6F0; color:#FFFFFF; border-color:#ACD6F0;} 

#nav li:hover li:hover li a.fly,
#nav li:hover li:hover li:hover li a.fly,
#nav li:hover li:hover li:hover li:hover li a.fly
{background:#ACD6F0; color:#FFFFFF; border-color:#ACD6F0;}