grid-template-rows: repeat(12, 1fr);
grid-template-columns: repeat(6, 1fr);
@media screen and (max-width: 575px) {
<div class="box">10</div>
<div class="box">11</div>
<div class="box">12</div>
<div class="box">13</div>
<div class="box">14</div>
<div class="box">15</div>
<div class="box">16</div>
<div class="box">17</div>
<div class="box">18</div>
<div class="box">19</div>
<div class="box">20</div>
<div class="box">21</div>
<div class="box">22</div>
<div class="box">23</div>
<div class="box">24</div>
<div class="box">25</div>
<div class="box">26</div>
<div class="box">27</div>
<div class="box">28</div>