genera un menu desplegable en forma horizontal

ul {
        list-style-type: none;
        margin: 0;
        padding: 0;
        overflow: hidden;
        background-color: #333;
    }
    
    li {
        float: left;
    }
    
    li a {
        display: block;
        color: white;
        text-align: center;
        padding: 14px 16px;
        text-decoration: none;
    }
    
    li a:hover:not(.active) {
        background-color: #111;
    }
    
    .active {
        background-color: #4CAF50;
    }