body {
    background-color: #151515;
}

html, body {
    margin: 0;
    height: 100%;
}

/* Canvas style from here: */
/* https://stackoverflow.com/questions/14043359/set-html-canvas-as-page-background#38473767 */
canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}