h5 { margin-block: 1.67em; font-size: 0.83em; font-weight: bold; }

h6 { margin-block: 2.33em; font-size: 0.67em; font-weight: bold; }</code></pre>

<p>In the following CSS block, <var>x</var> is shorthand for the following selector:

<code data-x="">:is(article, aside, nav, section)</code></p>

<pre><code class="css">@namespace "http://www.w3.org/1999/xhtml";

<var>x</var> h1 { margin-block: 0.83em; font-size: 1.50em; }

<var>x</var> <var>x</var> h1 { margin-block: 1.00em; font-size: 1.17em; }

<var>x</var> <var>x</var> <var>x</var> h1 { margin-block: 1.33em; font-size: 1.00em; }

<var>x</var> <var>x</var> <var>x</var> <var>x</var> h1 { margin-block: 1.67em; font-size: 0.83em; }

<var>x</var> <var>x</var> <var>x</var> <var>x</var> <var>x</var> h1 { margin-block: 2.33em; font-size: 0.67em; }</code></pre>

<p class="note">The shorthand is used to keep this block at least mildly readable.</p>

<h4>Lists</h4>