<!-- BEGIN COPY / PASTE -->
    <style>
      .grid-container {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
        gap: 10px;
      }
      
      @media (max-width: 600px) {
        .grid-container {
          grid-template-columns: 1fr;
        }
      }
    </style>

    <div class="grid-container">
      <div>Item 1</div>
      <div>Item 2</div>
      <div>Item 3</div>
      <div>Item 4</div>
    </div>
    <!-- END COPY / PASTE -->