@media screen and (max-width:1200px) {
    .nav-justified .nav-item {
        flex-basis: unset;
        flex-grow: unset;
        width: 25%;
        margin-bottom: 10px;
    }
}

@media screen and (max-width:600px) {
    .nav-justified .nav-item {
        width: 100%;
    }
}