You can use counters to do so:
The following style sheet numbers nested list items as “1”, “1.1”, “1.1.1”, etc.
OL { counter-reset: item } LI { display: block } LI:before { content: counters(item, ".") " "; counter-increment: item }
Example
ol { counter-reset: item }
li{ display: block }
li:before { content: counters(item, ".") " "; counter-increment: item }
<ol>
<li>li element
<ol>
<li>sub li element</li>
<li>sub li element</li>
<li>sub li element</li>
</ol>
</li>
<li>li element</li>
<li>li element
<ol>
<li>sub li element</li>
<li>sub li element</li>
<li>sub li element</li>
</ol>
</li>
</ol>
See Nested counters and scope for more information.