html {
    background-image: linear-gradient(to bottom right, #888888, #000000);
}

body {
    font-family: "Arial Black", sans-serif;
    margin: auto;
}

canvas {
    padding-left: 0;
    padding-right: 0;
    margin-left: auto;
    margin-right: auto;
    display: block;
}

header {
    color: #00AA00;
    text-align: center;
}

footer {
    background-color: #000000;
    color: #22AA22;
    text-align: center;
}