.responsive-grid {
    display: grid;
    grid-template-columns: 1fr; /* Mobile-first: 1 column */
    gap: 20px;
    width: 100%;
  }

  /* Desktop View */
  @media (min-width: 768px) {
    .responsive-grid {
      grid-template-columns: 1fr 1fr; /* 2 equal columns */
    }
    
    /* Force Cards 1 and 4 to span both columns */
    .card-full-width {
      grid-column: 1 / -1;
    }
  }