JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
  <div class="block"></div>
  <div class="block block--2"></div>
</div>

CSS

.parent {
  display: flex;
}
.block {
  width: 50px;
  height: 50px;
  border: 2px solid black;
}

.block--2 {
  margin-left: auto;
}