main.css

body {
    height: 100%;
    width: 100%;
    padding: 0;
    margin: 0;
    background-color: #1a1a1a;
}

#fps {
    position: absolute;
    top: 3px;
    left: 3px;
    z-index: 1000;
    font-size: 1.3rem;
    font-family: helvetica;
    user-select: none;
    color: white;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
    padding: 0;
    margin: 0;
    z-index: -1;
}