#mainnav ul li {
    position: relative;
}

#mainnav ul.submenu {
    position: absolute;
    left: 0;
    top: 150%;
    width: 250px;
    text-align: left;
    background-color: #F4F6F7FF;
    z-index: 9999;
    -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=0)";
    filter: alpha(opacity=0);
    opacity: 0;
    visibility: hidden;
    -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    -ms-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
}
#mainnav ul.submenu li:first-child {
    border-top: none;
}
#mainnav ul.submenu > li {
    border-top: 1px solid #333333;
}
#mainnav ul li ul li {
    margin-left: 0;
}
#mainnav ul.submenu > li > a {
    display: block;
    color: black;
    text-decoration: none;
    padding: 0 0 0 20px;
    line-height: 45px;
    -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    -ms-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
}
#mainnav ul li:hover > ul.submenu {
    top: 100%;
    -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
    filter: alpha(opacity=100);
    opacity: 1;
    visibility: visible;
}