<ol>
	<li>item</li>
	<li>item</li>
	<li>item</li>
	<li>item</li>
	<li>item</li>
	<li>item</li>
</ol>
ol {
	list-style: none;
	counter-reset: i;
}

ol li {
	counter-increment: i;
	font-size: 30px;
	padding: 5px 10px;
}

ol li:nth-child(even) {
	background-color: #ccc;
}

ol li:before {
	content: counter(i) ".";
	display: inline-block;
	background-color: #fff;
	color: red;
	width: 40px;
	height: 40px;
	font-weight: bold;
	border: 2px solid red;
	border-radius: 50%;
	text-align: center;
	line-height: 40px;
	margin-right: 20px;
}

External CSS

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External JavaScript

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