Responsive Site using Grid

I had a hard time getting the cards to stop stretching even though I had place-items: center; Two cards would stretch and fill the grid cell, but the others wouldn't. I just had to put the sizes like this to get it to work:

 .list_of_cards {
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(2, 15.625rem);
  }

  .card {
    max-width: 21.875rem;
    height: 15.625rem;
  }