<p class="instructions">
  (click here and <code>TAB</code> to the button, or
  click it with your mouse)
</p>
<button>Click Me!</button>
<!-- Load the :focus-visible polyfill -->
<script src="https://unpkg.com/focus-visible"></script>

/* Copyright 2018 Google LLC.
SPDX-License-Identifier: Apache-2.0 */

body {
  font-family: "Benton Sans", "Helvetica Neue", helvetica, arial, sans-serif;
  margin: 2em;
}

.instructions {
  margin: 8px;
}

.js-focus-visible button.focus-visible {
  outline: 4px dashed orange;
}