CSS Horizontal Navigation

                                          /* Horizontal Main Nav----------------------------------------------------------------------------------------------------*/div#mainnav {
    position: relative;
    z-index: 100;
    padding: 0px 0 0 0px;
}
 div#mainnav ul {
    padding: 0px;
    margin: 0px;
    list-style-type: none;
}
 div#mainnav li {
    float: left;
    position: relative;
    margin: 0px;
    padding: 0px;
    list-style-type: none;
}
 /* style the links for the top level */ div#mainnav a {
    font-size: 12px;
    height: 19px;
    color: #1a1a1a;
    text-decoration: none;
    text-align: center;
    padding: 9px 12px;
    display: block;
    font-weight: bold;
    text-transform: uppercase;
    width: auto;
    margin: 0;
}
 /* Style the first navigation button */div#mainnav li:first-child a {
}
 div#mainnav ul li a.current {
    background-color: #000;
}
 div#mainnav a:hover, div#mainnav ul li:hover {
    color: #FFCC00;
    background: #354356;
}
 /* Drop Down CSS----------------------------------------------------------------------------------------------------*/div#mainnav ul ul {
    visibility: hidden;
    position: absolute;
    height: 0;
    top: 41px;
    left: 0;
    z-index: 98;
}
 /* style the second level links */div#mainnav ul ul a, div#mainnav ul ul a:visited {
    background: #4c637e;
    color: #fff;
    height: auto;
    padding: 12px 5px;
    width: 200px;
    border-width: 0 1px 1px 1px;
}
 /* Style the first drop down navigation button */div#mainnav ul ul li:first-child a {
}
 div#mainnav ul ul a:hover, div#mainnav:hover > a, div#mainnav ul ul:hover > a {
    color: #FFCC00;
    background: #354356;
}
 /* style the third level background */div#mainnav ul ul ul {
    left: 211px;
    top: 0px;
    width: 129px;
    position: absolute;
    z-index: 99;
}
 div#mainnav ul ul ul a, div#mainnav ul ul ul a:visited {
    background: #FFCC00;
    color: #000;
}
 /* Style the first drop down navigation button of a drop down */div#mainnav ul ul ul li:first-child a {
}
 div#mainnav ul ul ul a:hover {
    color: #FFCC00;
    background: #354356;
}
 /* style the table so that it takes no part in the layout - required for IE to work */div#mainnav table {
    position: absolute;
    top: 0;
    left: 0;
    border-collapse: collapse;
}
 /* make the second level visible when hover on first level list OR link */div#mainnav ul li:hover ul, div#mainnav ul a:hover ul {
    visibility: visible;
}
 /* keep the third level hidden when you hover on first level list OR link */div#mainnav ul:hover ul ul {
    visibility: hidden;
}
 /* make the third level visible when you hover over second level list OR link */div#mainnav ul:hover ul :hover ul {
    visibility: visible;
}