menu3lavel.css

help.css

nav ul ul{
    display: none;
}
nav ul li:hover>ul{
    display: block;
}

nav ul{
    background: linear-gradient(180deg, rgb(169, 139, 230) 28%, rgb(90, 140, 250) 70%);
    background-color: #efefef;
    box-shadow: 0 0 9px rgba(0, 0, 0, 0.16);
    padding: 0 20px;
    border-radius: 10px;
    list-style: none;
    position: relative;
    display: inline-table;
}

nav ul li{
    float: left;
}
nav ul li:hover{
    background-color: #a78686;
}
nav ul li a{
    display: block;
    padding: 25px 40px;
    text-decoration: none;
    color: #2b650c;
}
nav ul li a:hover{
    color: #fff;
}
nav ul ul{
    background-color: #625757;
    border-radius: 0;
    padding: 0; 
    position: absolute;
    top: 100%;
}
nav ul ul li{
    float: none;
    border-bottom: 1px solid #000;
    border-top: 1px solid #000;
    position: relative;
}
nav ul ul li a{
    padding: 15px 40px;
    color: #fff;
}
nav ul ul li a:hover{
    color: #db1919
}
nav ul ul ul{
    position: absolute;
    top: 0;
    left: 100%;
}