* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
}

footer {
    position: fixed;
    left: 0;
    bottom: 0;
    width: 100%;
    background-color: transparent;
    color: white;
    text-align: center;
}

footer #extra {
    color: rgba(0,0,0,0.7);
    font-size: larger;
    text-decoration: underline;
}

footer a {
    text-decoration: underline;
    color: inherit;
}

@media only screen and (max-width: 420px) {
    footer {
        visibility: hidden;
        display: none;
    }
}