.md-typeset .grid.cards.cards-3 {
  /* The default is usually around 16rem. Adjust 12rem up or down to fit your layout. */
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 10rem), 1fr));
}

.md-typeset .grid.grid-3 {
  /* Lowering the minimum width from the 16rem default */
  grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr));
}