css background repeating-linear graddient code example
Example: repeating-linear-gradient
body {
background-image: repeating-linear-gradient(-45deg,
transparent,
transparent 20px,
black 20px,
black 40px);
/* with multiple color stop lengths */
background-image: repeating-linear-gradient(-45deg,
transparent 0 20px,
black 20px 40px);
}