glcanvas/style.css

* {
    margin: 0;
    padding: 0;

    box-sizing: border-box;
}

body {
    overflow: hidden;
}

canvas {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    min-height: 100vh;
    min-width: 100vw;
    box-sizing: border-box;
    image-rendering: pixelated;
}