Menú horizontal y submenú con CSS

/*****MENU DE NAVEGACION *****/
 
#nav{ width:900px;overflow:hidden;
 background-image:url(nav-bg.gif); /** fondo de barra de menus **/
 background-repeat:repeat-x;
 height:36px;
 float:left;}    
.catnav{float:left;
 width:750px;
 
 }
 
.catnav ul {
 list-style: none;  
 margin-left:0px;
 margin-top:0em;
 padding:0em;
 }
 
.catnav li {
float: left;
margin: 0;
margin-left:0;
padding: 0;
list-style-type: none;
}
 
.catnav a {
 display: block;
 line-height: 36px;
 margin: 0;
 padding: 0 10px;
 
 font-size: 12pt;
 color: #1DA4EA;
 font-family: Arial, Helvetica, sans-serif;
 background:url(navbg-2.gif) ;  /** fondo de opciones de menu **/
 list-style-type: none;
 text-decoration:none;
 letter-spacing: -1px;
 }
 
.catnav li ul {
float:left;
margin:0;
padding:0;
}
 
.catnav li a:hover {
 color: #fffffb;
 text-decoration: none;
 background:#F06C6C;
 }
 
.catnav li ul {
 list-style: none;
 position: absolute;
 width: 100px;
 left: -999em;
 }
 
.catnav li:hover ul, #nav li.sfhover ul {
 left: auto;
 }
 
.catnav li li {
 float: left;
 margin: 0;
 padding: 0;
 }
 
.catnav li li a {
 height: 36px;
 line-height: 36px;
 color: #fff;
 background:#F06C6C;
 margin: 0;
 padding: 0 10px;
 }
 
.catnav li li a:hover {
 background:#F06C6C;
 padding: 0 10px;
 }
 
.catnav li:hover, .catnav li.sfhover { /* prevents IE7 drop-down menu bug (focus on a page 
 
element prevents nested menus from disappearing) */
 position: static;overflow:hidden;
 }

<div id="nav">
<div class="catnav">	       
<ul class="nav">
 <li><a href="http://www.janmi.com/">Home</a></li>
 <li class="page_item page-item-7"><a href="http://www.janmi.com/portafolio" title="Portafolio">Portafolio</a></li>
 <li class="page_item page-item-14"><a href="http://www.janmi.com/" title="Eventos">Eventos</a>
 <ul>
	<li class="page_item page-item-22"><a href="http://www.janmi.com/" title="">Sub p&aacute;gina 1</a></li>
	<li class="page_item page-item-19"><a href="http://www.janmi.com/" title="">Sub p&aacute;gina 2</a></li>
 </ul>
 </li>
 <li class="page_item page-item-18"><a href="http://www.janmi.com/" title="Segunda Mano">Segunda Mano</a></li>   
</ul>
</div>
</div>