body {
  background: 
  linear-gradient(135deg, black 25%, transparent 25%) -50px 0,
  linear-gradient(225deg, black 25%, transparent 25%) -50px 0,
  linear-gradient(315deg, black 25%, transparent 25%),
  linear-gradient(45deg, black 25%, transparent 25%);	
  background-size: 2em 2em;
  background-color: #232323;
}