JSFiddle - React, Tailwind, and code Playground

HTML

<div class='wrapper'>
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
</div>
<div class='wrapper'>
  <div>5</div>
  <div>6</div>
  <div>7</div>
  <div>8</div>
</div>

CSS

* {
  box-sizing: border-box;
}

.wrapper {
  display: flex;
  flex-wrap: wrap;
}

.wrapper>* {
  padding: 1em;
  background-color: grey;
  border: 1px solid black;
  flex: 0 1 25%;
}

@media (max-width: 768px) {
  .wrapper>* {
    flex: 0 1 33.33%;
  }
}