<html>
<head>
<style>
body {
  background-color:#000;
  background-image: linear-gradient(white 2px, transparent 2px),
  linear-gradient(90deg, white 2px, transparent 2px),
  linear-gradient(rgba(255,255,255,.3) 1px, transparent 1px),
  linear-gradient(90deg, rgba(255,255,255,.3) 1px, transparent 1px);
  background-size: 100px 100px, 100px 100px, 20px 20px, 20px 20px;
  background-position:-2px -2px, -2px -2px, -1px -1px, -1px -1px;
}
</style>
</head>
<body>
<script>
function start() {
}
document.addEventListener('DOMContentLoaded', start);
</script>
</body>
</html>