title: Can a <small> tag be inside an HTML5 heading (i.e. h1, h2, h3, etc...)?
body: <p>I'm not sure about the convention regarding headings in HTML5, but I wanted to know if I could add a <code>&lt;small&gt;</code> in a <code>&lt;h3&gt;</code>, like this (this could apply to any tag inside any heading tags):</p>
  <pre><code>&lt;h3&gt;Payment details &lt;small&gt;(this is your default card)&lt;/small&gt;&lt;/h3&gt;
  </code></pre>