Fenced divs are containers for sequences of blocks, to which an attribute can be attached.
A fenced div begins with an opening fence: a line with three or
more consecutive : characters, followed by an attribute
specifier, followed by optional whitespace and the end of the
line.
It ends with a closing fence: a line beginning with at
least as many consecutive : characters as in the opening
fence, followed by optional whitespace and the end of the line.
If the end of the input (or enclosing block) is encountered before a closing fence, the fenced div is implicitly closed.
::: {#bar .foo}
Hi
> A block quote.
:::
.
<div id="bar" class="foo">
<p>Hi</p>
<blockquote>
<p>A block quote.</p>
</blockquote>
</div>
:::: {#bar .foo}
Hi
> A block quote.
:::::::::::::::::::::::::
.
<div id="bar" class="foo">
<p>Hi</p>
<blockquote>
<p>A block quote.</p>
</blockquote>
</div>
Fenced divs may be nested.
::: {#bar .foo}
Hi
::: {.baz}
> A block quote.
:::
:::
.
<div id="bar" class="foo">
<p>Hi</p>
<div class="baz">
<blockquote>
<p>A block quote.</p>
</blockquote>
</div>
</div>
A fenced div can interrupt a paragraph, without an intervening blank line.
Paragraph text
::: {#bar .foo}
Hi
:::
.
<p>Paragraph text</p>
<div id="bar" class="foo">
<p>Hi</p>
</div>
A fenced div must have attributes.
:::
Hi
:::
.
<p>:::
Hi
:::</p>
The closing fence must be at leats as long as the opening fence.
::::: {.foo}
Hi
:::
::::::
.
<div class="foo">
<p>Hi
:::</p>
</div>
If the end of the input (or enclosing block) is encountered before a closing fence, the fenced div is implicitly closed.
> ::: {.foo}
> Hi
.
<blockquote>
<div class="foo">
<p>Hi</p>
</div>
</blockquote>
Instead of a normal attribute specifier in curly braces, a single bare word may be used; it will be treated as a "class" attribute:
::: c_d
Hi
:::
.
<div class="c_d">
<p>Hi</p>
</div>