.menu-ngang {
    list-style-type: none;
    background-color: blue;
    padding: 0;
    margin: 0;
    display: inline-block;
    width: 100%;
}

.menu-ngang > li {
    float: left;
    position: relative;
    border-right: 1px solid white;
}

.menu-ngang li a {
    display: block;
    color: white;
    text-decoration: none;
    padding: 10px 20px;
    white-space: nowrap;
}

.menu-ngang li:hover > a {
    background-color: oldlace;
    color: black;
}

.sub-menu, .sub-menu-2 {
    display: none;
    position: absolute;
    background-color: blue;
    list-style: none;
    padding: 0;
    min-width: 150px;
}

.menu-ngang li:hover > .sub-menu {
    display: block;
}

.sub-menu-2 {
    left: 100%;
    top: 0;
}

.sub-menu li:hover > .sub-menu-2 {
    display: block;
}