JSFiddle - React, Tailwind, and code Playground

HTML

<div class="boxes">
  <div class="box"></div>
  <div class="box"></div>
  <div class="box"></div>
  <div class="box"></div>
  <div class="box"></div>
  <div class="box"></div>
  <div class="box"></div>
</div>

SCSS

.boxes {
  max-width: 600px;
  background: #ccc;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  padding: 20px;
  margin: 60px auto 60px auto;
}

.box {
  width: 23%;
  height: 100px;
  background: #222;
  margin: 1%;
}

.boxes::after {
  content: "";
  flex: auto;
}