www.aklabs.net/css/dropdownMenu.css

/* ============================================================================================== 
This copyright notice must be kept untouched in the stylesheet at all times.
The original version of this stylesheet and the associated (x)html 
is available at http://www.script-tutorials.com/whirling-dropdown-menu/
Copyright (c) Script Tutorials. All rights reserved.
This stylesheet and the associated (x)html may be modified in any way to fit your requirements.
================================================================================================= */

* {
    margin: 0;
    padding: 0;
}
.container {
    background-repeat: no-repeat;
    background-attachment: fixed;
    overflow: hidden;
}

/* general styles */
.menu, .menu ul {
    list-style: none;
    padding: 0;
    margin: 0;
}
.menu {

}
.menu li {
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#292929', endColorstr='#252525');
    -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr='#292929', endColorstr='#252525')";
}
.menu > li {
    display: block;
    position: relative;
}
.menu > li:first-child {
}
.menu a {
    border-left: 3px solid rgba(0, 0, 0, 0);
    display: block;
    font-size: 23px;
    color: #fff; 
    text-decoration: none;
    text-transform: uppercase;
}

/* onhover styles */
.menu li:hover {

    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#1c1c1c', endColorstr='#1b1b1b');
    -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr='#1c1c1c', endColorstr='#1b1b1b')";
}
.menu li:hover > a {

}

/* submenu styles */
.submenu {
    left: 0;
    max-height: 0;
    position: absolute;
    top: 100%;
    width: 200%;
    z-index: 500;
    background-color: #fff;
    -webkit-perspective: 400px;
    -moz-perspective: 400px;
    -ms-perspective: 400px;
    -o-perspective: 400px;
    perspective: 400px;
}
.submenu li {

    opacity: 0;
    -webkit-transform: rotateY(90deg);
    -moz-transform: rotateY(90deg);
    -ms-transform: rotateY(90deg);
    -o-transform: rotateY(90deg);
    transform: rotateY(90deg);
    z-index: 500;
    -webkit-transition: opacity .4s, -webkit-transform .5s;
    -moz-transition: opacity .4s, -moz-transform .5s;
    -ms-transition: opacity .4s, -ms-transform .5s;
    -o-transition: opacity .4s, -o-transform .5s;
    transition: opacity .4s, transform .5s;
}
.menu .submenu li:hover a {
    z-index: 500;

}
.submenu li a{
    color: #000;
    font-size: 15px;
}
.menu > li:hover .submenu, .menu > li:focus .submenu {
    max-height: 2000px;
    z-index: 500;
}
.menu > li:hover .submenu li, .menu > li:focus .submenu li {
    opacity: 1;
    z-index: 500;
    -webkit-transform: none;
    -moz-transform: none;
    -ms-transform: none;
    -o-transform: none;
    transform: none;
}

/* CSS3 delays for transition effects */
.menu li:hover .submenu li:nth-child(1) {
    z-index: 500;
    -webkit-transition-delay: 0s;
    -moz-transition-delay: 0s;
    -ms-transition-delay: 0s;
    -o-transition-delay: 0s;
    transition-delay: 0s;
}
.menu li:hover .submenu li:nth-child(2) {
    z-index: 500;
    -webkit-transition-delay: 50ms;
    -moz-transition-delay: 50ms;
    -ms-transition-delay: 50ms;
    -o-transition-delay: 50ms;
    transition-delay: 50ms;
}
.menu li:hover .submenu li:nth-child(3) {
    z-index: 500;
    -webkit-transition-delay: 100ms;
    -moz-transition-delay: 100ms;
    -ms-transition-delay: 100ms;
    -o-transition-delay: 100ms;
    transition-delay: 100ms;
}
.menu li:hover .submenu li:nth-child(4) {
    z-index: 500;
    -webkit-transition-delay: 150ms;
    -moz-transition-delay: 150ms;
    -ms-transition-delay: 150ms;
    -o-transition-delay: 150ms;
    transition-delay: 150ms;
}
.menu li:hover .submenu li:nth-child(5) {
    z-index: 500;
    -webkit-transition-delay: 200ms;
    -moz-transition-delay: 200ms;
    -ms-transition-delay: 200ms;
    -o-transition-delay: 200ms;
    transition-delay: 200ms;
}
.menu li:hover .submenu li:nth-child(6) {
    z-index: 500;
    -webkit-transition-delay: 250ms;
    -moz-transition-delay: 250ms;
    -ms-transition-delay: 250ms;
    -o-transition-delay: 250ms;
    transition-delay: 250ms;
}
.menu li:hover .submenu li:nth-child(7) {
    z-index: 500;
    -webkit-transition-delay: 300ms;
    -moz-transition-delay: 300ms;
    -ms-transition-delay: 300ms;
    -o-transition-delay: 300ms;
    transition-delay: 300ms;
}
.menu li:hover .submenu li:nth-child(8) {
    z-index: 500;
    -webkit-transition-delay: 350ms;
    -moz-transition-delay: 350ms;
    -ms-transition-delay: 350ms;
    -o-transition-delay: 350ms;
    transition-delay: 350ms;
}

.submenu li:nth-child(1) {
    z-index: 500;
    -webkit-transition-delay: 350ms;
    -moz-transition-delay: 350ms;
    -ms-transition-delay: 350ms;
    -o-transition-delay: 350ms;
    transition-delay: 350ms;
}
.submenu li:nth-child(2) {
    z-index: 500;
    -webkit-transition-delay: 300ms;
    -moz-transition-delay: 300ms;
    -ms-transition-delay: 300ms;
    -o-transition-delay: 300ms;
    transition-delay: 300ms;
}
.submenu li:nth-child(3) {
    z-index: 500;
    -webkit-transition-delay: 250ms;
    -moz-transition-delay: 250ms;
    -ms-transition-delay: 250ms;
    -o-transition-delay: 250ms;
    transition-delay: 250ms;
}
.submenu li:nth-child(4) {
    z-index: 500;
    -webkit-transition-delay: 200ms;
    -moz-transition-delay: 200ms;
    -ms-transition-delay: 200ms;
    -o-transition-delay: 200ms;
    transition-delay: 200ms;
}
.submenu li:nth-child(5) {
    z-index: 500;
    -webkit-transition-delay: 150ms;
    -moz-transition-delay: 150ms;
    -ms-transition-delay: 150ms;
    -o-transition-delay: 150ms;
    transition-delay: 150ms;
}
.submenu li:nth-child(6) {
    z-index: 500;
    -webkit-transition-delay: 100ms;
    -moz-transition-delay: 100ms;
    -ms-transition-delay: 100ms;
    -o-transition-delay: 100ms;
    transition-delay: 100ms;
}
.submenu li:nth-child(7) {
    z-index: 500;
    -webkit-transition-delay: 50ms;
    -moz-transition-delay: 50ms;
    -ms-transition-delay: 50ms;
    -o-transition-delay: 50ms;
    transition-delay: 50ms;
}
.submenu li:nth-child(8) {
    z-index: 500;
    -webkit-transition-delay: 0s;
    -moz-transition-delay: 0s;
    -ms-transition-delay: 0s;
    -o-transition-delay: 0s;
    transition-delay: 0s;
}