.dropdown-content {
    display: none;
    position: absolute;
    z-index: 10;
}
.dropdown-content a {
    display: block;
}
.dropdown-content a:hover {
    background-color: #f1f1f1;
    color: black;
}

@media (min-width: 640px) {
    .dropdown-menu:hover .dropdown-content, .dropdown-menu:focus .dropdown-content {
        display: block;
    }
}