<!DOCTYPE html>
<html>
<head>
<style>
ol {
counter-reset: section;
list-style-type: none;
}
li::before {
counter-increment: section;
content: counters(section,".") " ";
}
</style>
</head>
<body>
<ol>
<li>item</li>
<li>item
<ol>
<li>item</li>
<li>item</li>
<li>item
<ol>
<li>item</li>
<li>item</li>
<li>item</li>
</ol>
</li>
<li>item</li>
</ol>
</li>
<li>item</li>
<li>item</li>
</ol>
<ol>
<li>item</li>
<li>item</li>
</ol>
</body>
</html>
====================Output========================
