ul#menu-main-menu {
    position: relative;
}
ul#menu-main-menu li.menu-item-has-children:hover ul.sub-menu {
    display: block;
}
ul#menu-main-menu ul.sub-menu {
    display: none;
    position: absolute;
    top: 1em;
    padding-top: 30px;
    left: 5.5em;
    z-index: 99999999999 !important;
    width: 180px;
    background: #fff;
    box-shadow: 0px 3px 3px rgba(0,0,0,0.2);
}

@media only screen and (max-width:1024px){
.menu-item-has-children li {
    display: none !important;
}
ul.sub-menu li {
    display: block !important;
}
}