style.css

footer{
    display: none !important;
}

td img{
  background-image:
    linear-gradient(45deg, lightgrey 25%, transparent 25%), 
    linear-gradient(135deg, lightgrey 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, lightgrey 75%),
    linear-gradient(135deg, transparent 75%, lightgrey 75%);
  
  background-size: 20px 20px;
  background-position: 0 0, 10px 0, 10px -10px, 0px 10px;
}