<style type="text/css">
<!--一级菜单-->
.menu {font-family: arial, sans-serif;width:983px; margin:0;}
.menu ul {padding:0; margin:0;list-style-type: none;}
.menu ul li {float:left; position:relative;}
.menu ul li a, .menu ul li a:visited {display:block; text-align:center;
text-decoration:none; width:80px; height:29px;padding-top:3px;color:#fff; font-size:14px;}
<!--二级菜单-->

.menu ul li ul {display: none;}
.menu ul li:hover a {color:yellow;background:url(/templets/mytp/images/nav_bg2.jpg)
 left top repeat-x;}
.menu ul li:hover ul {display:block; position:absolute; top:32px; left:0;
border:1px #2E679C solid;border-top:none;}
.menu ul li:hover ul li a {display:block; color:#000;width:120px;text-align:left;
border-bottom:1px #2E679C dashed;padding-left:18px;background:#F2F5F9 url(/templets/mytp/images/new.png) left center no-repeat;}
.menu ul li:hover ul li a:hover {color:#fff;text-align:left;padding-left:18px;
background:#2E679C url(/templets/mytp/images/new.png) left center no-repeat;}
<!--三级菜单-->

.menu ul li ul li ul{display:none;}
.menu ul li ul li:hover ul {display:block; position:absolute; top:0px;
left:138px; border:1px #2E679C solid;}
.menu ul li ul li:hover ul li a {display:block; color:#000;width:120px;
text-align:left;border-bottom:1px #2E679C dashed;padding-left:18px;background:#F2F5F9 rl(/templets/mytp/images/new.png) left center no-repeat;}
.menu ul li ul li:hover ul li a:hover {color:#fff;text-align:left;
padding-left:18px;background:#2E679C url(/templets/mytp/images/new.png) left center no-repeat;}</style>