html, body {
    height: 100%;
    width: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background: #111;
    background: url("background.png") no-repeat center center fixed;
    background-size: cover;
}

body {
    width: 100vw;
    height: 100vh;
}

#Canvas {
    display: block;
    margin: auto;
    box-shadow: 0 0 40px #000b, 0 0 0 3px #333;
    background: transparent;
    border-radius: 8px;
    position: absolute;
    top: 0; left: 0; bottom: 0; right: 0;
}