Simple dropdowns using the Custom Menu widget

gistfile1.css

.menu > li {
    display: inline-block;
    position: relative;
}
.menu > li > a {
    padding: 5px 10px;
    display: inline-block;
}
.menu li ul {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    margin-top: 0;
    background: #000;
    min-width: 180px;
}
.menu li ul li a {
    display: block;
}
.menu li:hover ul {
    display: block;
}