JSFiddle - React, Tailwind, and code Playground

HTML

<div class="circle">
  <span class="circle__number">
    1
  </span>
</div>

CSS

.circle {
  width: 100px;
  height: 100px;
  border-radius: 100px;
  background-color: red;
  display: flex;
  justify-content: center;
  align-items: center;
}

.circle__number {
  color: #fff;
  font-size: 70px;
  font-weight: bold;
  
}