puppeteer/test/assets/grid.html

<script>
document.addEventListener('DOMContentLoaded', function() {
    function generatePalette(amount) {
        var result = [];
        var hueStep = 360 / amount;
        for (var i = 0; i < amount; ++i)
            result.push('hsl(' + (hueStep * i) + ', 100%, 90%)');
        return result;
    }

    var palette = generatePalette(100);
    for (var i = 0; i < 1000; ++i) {
        var box = document.createElement('div');
        box.classList.add('box');
        box.textContent = i;
        box.style.setProperty('background-color', palette[i % palette.length]);
        document.body.appendChild(box);
    }
});
</script>

<style>

/* Hide scrollbar so that it is not captured on screenshots */
::-webkit-scrollbar {
    display: none;
}

body {
    margin: 0;
    padding: 0;
}

.box {
    font-family: arial;
    display: inline-block;
    margin: 0;
    padding: 0;
    width: 50px;
    height: 50px;
    box-sizing: border-box;
    border: 1px solid darkgray;
}
</style>