JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">
  <div>One</div>
  <div>Two</div>
  <div>Three</div>
  <div>Four</div>
  <div>Five</div>
  <div>Six</div>
</div>

CSS

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

.box div {
  flex: 1 0 15%;
  height: 50px;
  margin: 5px;
  background-color: yellow;
  border: 1px solid gray;
}

@media ( max-width: 800px) {
  .box div {
    flex-basis: 30%;
  }
}

@media ( max-width: 600px) {
  .box div {
    flex-basis: 40%;
  }
}

@media ( max-width: 400px) {
  .box div {
    flex-basis: 100%;
    margin: 0 0 5px 0;
  }
}

* {
  box-sizing: border-box;
}