JSFiddle - React, Tailwind, and code Playground

HTML

<div>

  <input type='checkbox' id='resize'>
  <label for='resize'>Resize</label>
  <div class="size" data-width=100px>

  </div>
</div>

CSS

input[type='checkbox']:checked ~ .size:before {
  content: attr(data-width);
  display: block;
  height: 30px;
  background-color: red;
  width: attr(data-width);
  /*width: 100px;*/
}