<ol>
	<li>one</li>
	<li>two</li>
	<li>three</li>
	<li>four</li>
	<li>five</li>
	<li>six</li>
	<li>seven</li>
	<li>eight</li>
	<li>nine</li>
	<li>ten</li>
	<li>eleven</li>
	<li>twelve</li>
</ol>

ol {
	list-style-type: none;
	counter-reset: li;
}
li {
	font-size: 2rem;
}

li:before {
  counter-increment: li;
  content: counter(li, decimal-leading-zero);
	color: red;
	margin-right: 0.25em;
}