JSFiddle - React, Tailwind, and code Playground

HTML

<div class="header">
  <div class="menu"></div>
</div>
<div class="content">
</div>

CSS

.header {
  position: relative;
  height: 150px;
  background: green;
}

.content {
  height: 300px;
  background: blue;
}

.menu {
  position: absolute;
  top: 100px;
  left: 50%;
  width: 200px;
  height: 200px;
  background: white;
  transform: translate(-50%, 0);
}