.menu-item{
    float: left;
}
nav ul{
    list-style: none;
}
nav a{
    text-decoration: none;
    Color: white; 
    padding: 10px;
    display: block;
}
nav ul, nav li{
    padding: 0px;
    margin: 0px;
    float: left;
}
nav li{
    word-wrap: break-word;
    background-color: gray;
}
nav{
    background-color: gray;
    overflow: auto;
}
.submenu{
    display: none;
    position: absolute;
}
.menu-item:hover .submenu{
    display: block;
}
nav li:hover{
    background-color: #444444;
    animation-name: miAnimacion;
    animation-duration: 2s;
}
@keyframes miAnimacion{
    from{
        background-color: gray;
        
    }
    to{
        background-color: #444444;
    }
}