index.html

<style>
    body{
        margin:0;
        background: #1a1a1a;
    }
    #c {
        position:fixed;top:50%;left:50%;translate:-50% -50%;
        image-rendering: pixelated;
    }
</style>
<canvas id="c"></canvas>
<script src="./main.js"></script>
<script>
    fl = Math.floor;
    a = c.getContext`2d`;
    u = _=>{
        w = innerWidth;
        h = innerHeight;
        wS = fl(w/256);
        hS = fl(h/256);
        s=Math.min(wS,hS);
        c.width = 256*s;
        c.height= 240*s;
        canvas.pixelRatio = s;
        canvas.setScale(canvas.scale);
        a.imageSmoothingEnabled = false;
    }
    u();addEventListener('resize', u, !0);
</script>