ul.dropdown {
 position: relative;
 z-index: 596;
}
ul.dropdown ul {
 display: none;
 position: absolute;
 top: 100%;
 left: 0;
 z-index: 597;
 width: 100%;
 padding:0;
 margin:0;
}
ul.dropdown ul ul {
 top: 2px;
 left: 100%;
}
ul.dropdown li {
 position: relative;
 z-index: 598;
}
ul.dropdown li:hover { z-index: 599; }
ul.dropdown > li { float: left; }
ul.dropdown li:hover > ul { display: block; }