Nested lists such as:

: foo
:: bar

have a bit of a styling problem. The HTML generated is:

<dl>
<dd>foo
<dl><dd>bar
</dd></dl></dd></dl>

and with this DOM tree there's no way to highlight/box foo with a CSS style without also surrounding bar.

What we'd like is HTML structure more like:

<dl>
<dd><div>foo</div>
<dl><dd>bar
</dd></dl></dd></dl>

or even

<dl>
<dd>foo
</dd><dd>
<dl><dd>bar
</dd></dl></dd></dl>

The former we could probably convince the legacy parser and/or Parsoid to emit; basically creating an initial <div> for the item and closing it as soon as a nested list is encountered. The latter would probably require new wikitext syntax (or flag, which could be set on certain types of pages), since it's a non-backwards-compatible change to the list semantics.

No specific proposal yet; this task is initially for discussion.