JSFiddle - React, Tailwind, and code Playground

HTML

<div contenteditable="true">
  <p>The first paragraph</p>
  <p>The second paragraph</p>
</div>

CSS

div:focus { outline: none; }

JavaScript

var selectedElement = null;
function setFocus(e) {
  if (selectedElement)
    selectedElement.style.outline = 'none';

  selectedElement = window.getSelection().focusNode.parentNode;
  selectedElement.style.outline = '1px solid #f00';
};
document.onkeyup = setFocus;
document.onmouseup = setFocus;