Solution of problem is her in fiddle : http://jsfiddle.net/7mvuw/
Demo: http://jsfiddle.net/7mvuw/embedded/result/
Note: I have changed the looks and feel but html structure is same, looks and feel for demo purpose you can adjust as per your requirement.
#access {
background: #000;
display: block;
float: left;
margin: 0 auto;
width: 940px;
}
#access .menu-header,
div.menu {
font-size: 13px;
margin-left: 12px;
width: 928px;
}
#access .menu-header ul,
div.menu ul {
list-style: none;
margin: 0;
}
#access .menu-header li,
div.menu li {
float: left;
position: relative;
}
#access a {
color: #aaa;
display: block;
line-height: 38px;
padding: 0 10px;
text-decoration: none;
}
#access ul ul {
box-shadow: 0px 3px 3px rgba(0,0,0,0.2);
-moz-box-shadow: 0px 3px 3px rgba(0,0,0,0.2);
-webkit-box-shadow: 0px 3px 3px rgba(0,0,0,0.2);
display: none;
position: absolute;
top: 38px;
left: 0;
float: left;
width: 180px;
z-index: 99999;
padding-left:0;
}
#access ul ul li {
min-width: 180px;
}
#access ul ul ul {
left: 100%;
top: 0;
}
#access ul ul a {
background: #333;
line-height: 1em;
padding: 10px;
width: 160px;
height: auto;
}
#access li:hover > a,
#access ul ul :hover > a {
background: #333;
color: #fff;
}
#access ul li:hover > ul {
display: block;
}
#access ul li.current_page_item > a,
#access ul li.current-menu-ancestor > a,
#access ul li.current-menu-item > a,
#access ul li.current-menu-parent > a {
color: #fff;
}