JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main">
    <!-- your content -->
</div>
<div class="fake-wrapper">
    <div class="fixed">
        <a href="/">click!</a>
    </div>
</div>

CSS

.main {
      /*just for visualisation*/
      width: 300px;
      height: 1500px;
      background: #ccc;
    }
    .main,
    .fake-wrapper {
      float: left;
    }
    .fixed {
      position: fixed;
      top: 50%;
    }