.body{
    margin:0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
}

.topnav{
    overflow: hidden;
    background-color: #333;
}

.topnav a{
    float:  left;
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 17px;
    transition: 0.3s ease-in-out;
}

.topnav a:hover{
    background-color: aqua;
    color: black;
}

.topnav .icon{
    display: none;
}

@media screen and (max-width:500px){
    .topnav a:not(:first-child) {display: none;}
    .topnav a.icon{
        float: right;
        display: block;
        transition: 0.3s ease-in-out;
    }
}

@media screen and (max-width: 500px){
    .topnav.responsive{
        position: relative;
        transition: 0.3s ease-in-out;
    }

    .topnav.responsive .icon{
        position: absolute;
        right: 0;
        top: 0;
        transition: 0.3s ease-in-out;
    }

    .topnav.responsive a{
        float: none;
        display: block;
        text-align: left;
        transition: 0.3s ease-in-out;
    }
}