<p>The following typographic conventions are used in this specification:</p>
<dl class="typography">
<dt><code>markup</code></dt><dd>
Markup (elements, attributes, properties),
machine processable values (string, characters, media types),
property name,
or a file name is in red-orange monospace font.</dd>
<dt><var>variable</var></dt><dd>
A variable in pseudo-code or in an algorithm description is in italics.</dd>
<dt><dfn data-no-xref="">definition</dfn></dt><dd>
A definition of a term, to be used elsewhere in this or other specifications,
is in bold and italics.</dd>
<dt><a data-lt="definition">definition reference</a></dt><dd>
A reference to a definition <em>in this document</em>
is underlined and is also an active link to the definition itself. </dd>
<dt><a data-lt="definition"><code>markup definition reference</code></a></dt><dd>
References to a definition <em>in this document</em>,
when the reference itself is also a markup, is underlined,
red-orange monospace font, and is also an active link to the definition itself.</dd>
<dt><a class="externalDFN">external definition reference</a></dt><dd>
A reference to a definition <em>in another document</em>
is underlined, in italics, and is also an active link to the definition itself.</dd>
<dt><a class="externalDFN"><code> markup external definition reference</code></a></dt><dd>
A reference to a definition <em>in another document</em>,
when the reference itself is also a markup,
is underlined, in italics red-orange monospace font,
and is also an active link to the definition itself.</dd>
<dt><a href="">hyperlink</a></dt><dd>
A hyperlink is underlined and in blue.</dd>
<dt>[<a href="">reference</a>]</dt><dd>
A document reference (normative or informative) is enclosed in square brackets
and links to the references section.</dd>
<dt class="changed">Changes from Recommendation</dt><dd>
Sections or phrases changed from the previous Recommendation
may be <span class="changed">highlighted</span> using a control
in <a href="#how-to-read-this-document" class="sectionRef"></a>.</dd>
</dl>
<p class="note">Notes are in light green boxes with a green left border and with a "Note" header in green.
Notes are always informative.</p>
<pre class="example nohighlight">
Examples are in light khaki boxes, with khaki left border,
and with a numbered "Example" header in khaki.
Examples are always informative. The content of the example is in monospace font and may be syntax colored.
Examples may have tabbed navigation buttons
to show the results of transforming an example into other representations.
</pre>