.alternating-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.wide { grid-column: span 2; }
.tall { grid-row: span 2; }
img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 8px;
}