body {
background-image: linear-gradient(45deg, transparent 20%, black 25%, transparent 25%),
linear-gradient(-45deg, transparent 20%, black 25%, transparent 25%),
linear-gradient(-45deg, transparent 75%, black 80%, transparent 0),
radial-gradient(gray 2px, transparent 0);
background-size: 30px 30px, 30px 30px;
}
This Pen doesn't use any external CSS resources.
This Pen doesn't use any external JavaScript resources.