<div class="instructions">
  (click here, then press <code>TAB</code>)
</div>
<div tabindex="0" class="focusable">
  Focus me with the TAB key
</div>
<div tabindex="0" class="focusable">
  Focus me with the TAB key
</div>

body {
  font-family: "system-ui", sans-serif;
  margin: 2em;
}

.instructions {
  margin: 8px;
}

.focusable {
  display: inline-block;
  border: 2px solid black;
  border-radius: 8px;
  padding: 8px;
  margin: 8px;
}

div:focus {
  outline: 4px dashed darkorange;
}