.thumbnails {
  display: flex;
  flex-direction: column;
  line-height: 0;
  
  li {
    flex: auto; 
  }

  a {
    display: block;
  }
  
  img {
    width: 30vmin;
    height: 20vmin;
    object-fit: cover;
    object-position: top;
  }
}