nav {
    overflow: visible;
    background-color: #333;
}

nav a, a:visited {
    display: block;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 17px;
}

nav a:hover {
    background-color: #ddd;
    color: black;
    text-decoration: none;

}

nav a.active {
    background-color: #4CAF50;
    color: white;
}

nav .icoOOn {
    display: none;
}

@media screen and (max-width: 600px) {
    nav a:not(:first-child) {
        display: none;
    }

    nav a.icoOOn {
        float: right;
        display: block;
    }
}

@media screen and (max-width: 600px) {
    nav.responsive {
        position: relative;
    }

    nav.responsive .icoOOn {
        position: absolute;
        right: 0;
        top: 0;
    }

    nav.responsive a {
        float: none;
        display: block;
        text-align: left;
    }
}

nav .dropdown-menu {
    background-clip: padding-box;
    background-color: #6c757d;
}
nav a:visited{ color: white; }