JSFiddle - React, Tailwind, and code Playground

HTML

<div class="list-container">
    <div class="cont">
      <div class='itemA'>1</div>
      <div class='itemA'>2</div>
      <div class='itemA'>3</div>
      <div class='itemA'>4</div>
    </div>

    <div class="cont contB">
      <div class='itemB'>1</div>
      <div class='itemB'>2</div>
      <div class='itemB'>3</div>
      <div class='itemB'>4</div>
    </div>
</div>

CSS

.itemA,
.itemB {
  width: 50px;
  height: 50px;
}
.itemA {
  background: green;
}
.itemB {
  background: red;
}
.list-container {
    float: right;
}
.cont,
.cont div {
    float: left;
}