HTML
<div class="parent white">
<div class="box">1</div>
<div class="box">2</div>
<div class="box">3</div>
<div class="box">4</div>
</div>
CSS
.parent {
display: grid;
grid-gap: 1rem;
grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}