JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <!-- Other elements here -->
  <div id="copyright">
    Copyright Foo web designs
  </div>
</div>

CSS

#container {
    /* So the #container most have a fixed height */
    height: 300px;
    line-height: 300px;
    background:Red;
}

#container > * {
    /* Restore Line height to Normal */
    line-height: 1.2em;
}

#copyright {
    display:inline-block;
    vertical-align:bottom;
    width:100%; /* Let it be a block */
    background:green;
}