<p>Вибери потрібне значення для <code>outline-width</code>:</p>

<input type="number" class="input" min="0" value="16" id="val" onchange="change(this.value)"></input>

<div id="block"></div>
body {
	padding: 36px;
  text-align: center;
  line-height: 1.45;
  font-size: 20px;
  font-family: sans-serif;
  counter-reset: chapter 2;
}

.input {
  margin-bottom: 16px;
  padding: 1px;
  font-size: 13px;
}

#block {
  padding: 36px;
  width: 275px;
  margin: 75px auto 0 auto;
  border: 8px solid #666;
  outline: 16px solid #000;
  transition: all .15s ease-in;
}
function change(val) {
  block.style.outlineWidth = val + 'px';
}

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