JSFiddle - React, Tailwind, and code Playground

HTML

<header style="background-color: yellow">
  <div class="aaa" style="background-color:red;"></div>
  <div class="bbb" style="background-color:blue;"></div>
  <div class="ccc" style="background-color:green;"></div>
</header>

CSS

body {
  padding: 0;
  margin: 0;
}

header{
  width: 100%;
  height: 120px;
}
div {
  height: 30px;
  width: 30px;
}

.aaa {
  position: relative;
  top: 50%;
  transform: translateY(-50%);
  margin: 0 auto;
}

.bbb {
  top: 50%;
  transform: translateY(-50%);
}

.ccc {
  top: 50%;
  transform: translateY(-50%);
  float: right;
}