div {
width: 1000px;
height: 25px;
background:
linear-gradient(135deg, transparent, transparent 45%, #333, transparent 55%, transparent 100%),
linear-gradient(45deg, transparent, transparent 45%, #333, transparent 55%, transparent 100%);
background-size: 50px 50px;
background-repeat: repeat-x, repeat-x;
}