body {
  font-family: 'Fira Sans', Arial, Helvetica, sans-serif;
  background: linear-gradient(45deg, transparent 49%, #808080 49% 51%, transparent 51%) , linear-gradient(-45deg, transparent 49%, #808080 49% 51%, transparent 51%);
  background-size: 2em 2em;
  background-color: #575757;
  opacity: 1
}