.menu {
    list-style: none;
    margin: 0;
    padding: 0;
    background: blue;
    display: flex;
}

.menu li {
    position: relative;
    flex: 1;
    text-align: center; 
}


.menu li a {
    display: block;
    padding: 12px 20px;
    color: white;
    text-decoration: none;
    border-right: 1px solid white;
}


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

.menu .submenu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: blue;
    list-style: none;
    padding: 0;
    margin: 0;
    width: 200px;
    z-index: 100;
}

.menu .submenu li a {
    border-bottom: 1px solid white;
}

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

.menu .submenu .has-sub:hover > .submenu {
    display: block;
    top: 0;
    left: 100%;
}

.menu .submenu .submenu li a {
    border-bottom: 1px solid white;
}