.center-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 15px;
}

@media only screen and (min-width: 768px) {
  /* For desktop: */
  .center-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  gap: 15px;
  height: auto;
  margin: 70px;
	object-fit: cover;
}