body, html {
    height: 100%;
}

body::before {
    content: "";
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: -1;

    background-image: url('../img/back-skull.png');
    background-size: cover;
    background-attachment: fixed;
    filter: opacity(0.2);
}

body {
    background-color: black;
    color: white;
    margin: 0;
    font-family: 'Montserrat', sans-serif;
    display: flex;
    flex-direction: column;
}


main {
    flex: 1;
}