What's wrong with this level-3 heading?
<h3 Level 3 Heading<h3>
<h3> should be <h4>
<h3>
<h4>
<h3> should be inside a <header> tag
<header>
Level 3 Heading should be inside a <span>
Level 3 Heading
<span>
<h3 Level 3 Heading<h3> should be <h3>Level 3 Heading</h3>
<h3>Level 3 Heading</h3>