.grid {
  background-color: transparent;
  background-image:
    linear-gradient(0deg,
      transparent,
      transparent 50%,
      rgba(0, 0, 0, 0.05) 51%,
      rgba(0, 0, 0, 0.05)
    ),
    linear-gradient(90deg,
      transparent,
      transparent 50%,
      rgba(0, 0, 0, 0.05) 51%,
      rgba(0, 0, 0, 0.05)
    );
  background-size: 3em 3em;
}

.blocks * {
  background-color: rgba(255, 255, 0, 0.3);
}