p the bedrock of <abbr>TCP/IP</abbr>.</p>

<p>Each of the web’s shearing layers can be peeled back to reveal a layer below. Running that process in reverse—applying each layer in turn—is a key principle of resilient web design.</p>

<section aria-labelledby="progressiveenhancement">

<h2 id="progressiveenhancement">Progressive enhancement</h2>

<p>In 2003, the <span id="South%20by%20Southwest">South by Southwest</span> festival in Austin, Texas was primarily an event for musicians and filmmakers. To