body {
  margin: 0;
  padding: 0;
  height: 100vh;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  
  background:
    radial-gradient(circle, #2b1a0f 18%, transparent 19%) 0 0,
    radial-gradient(circle, #2b1a0f 18%, transparent 19%) 25px 25px,
    radial-gradient(circle, rgba(0,0,0,0.3) 20%, transparent 21%) 0 0,
    radial-gradient(circle, rgba(0,0,0,0.3) 20%, transparent 21%) 25px 25px;
  background-size: 50px 50px;

  animation: roll 2s linear infinite, flicker 1.2s infinite alternate;
}


@keyframes roll {
  from {
    background-position: 0 0, 25px 25px, 2px 2px, 27px 27px;
  }
  to {
    background-position: 50px 50px, 75px 75px, 52px 52px, 77px 77px;
  }
}

@keyframes flicker {
  0% {
    filter: brightness(0.85);
  }
  50% {
    filter: brightness(1.4);
  }
  100% {
    filter: brightness(1);
  }
}