JSFiddle - React, Tailwind, and code Playground

HTML

<div class="flex-container">
  <div class="flex-item">
    test
  </div>
  <div class="flex-item">
    test
  </div>
</div>

CSS

.flex-container {
  height: 100%;
  display: flex;
  flex-direction: column;
  flex-wrap: nowrap;
  justify-content: center;
  align-content: stretch;
  align-items: stretch;
}

.flex-item {
  flex: 1 auto;
  display: flex;
  align-items: center;
  height: 200px;
  background-color: royalblue;
  color: white;
}

.flex-item:nth-of-type(2) {
  background-color: tomato;
}