body {
    font-family: Arial;
}

/* MENU CHA */
#menu {
    list-style: none;
    padding: 0;
    width: 150px;
}

#menu > li {
    position: relative;
}

/* LINK */
#menu a {
    display: block;
    background: #000;
    color: #FFF;
    padding: 10px;
    text-decoration: none;
    border-bottom: 1px solid #FFF;
}

/* HOVER */
#menu a:hover {
    background: darkgray;
}

/* SUBMENU cấp 2 */
#submenu {
    list-style: none;
    padding: 0;
    position: absolute;
    left: 150px;
    top: 0;
    display: none;
    width: max-content;
}

/* SUBMENU cấp 3 */
#submenu-2 {
    list-style: none;
    padding: 0;
    position: absolute;
    left: 100%;
    top: 0;
    display: none;
    width: max-content;
}
#submenu li {
    position: relative;
}

/* HIỆN MENU CON */
#has-sub:hover > #submenu {
    display: block;
}

#has-sub-2:hover > #submenu-2 {
    display: block;
}