Make preview section contenteditable

Author: nikitahl

index.html

@@ -57,7 +57,7 @@ <h1 class="site-heading">CSS Base</h1>
 					<a class="github-button" href="https://github.com/nikitahl/css-base" data-color-scheme="no-preference: light; light: light; dark: light;" aria-label="Star nikitahl/css-base on GitHub">GitHub</a>
 				</div>
 		</div>
-		<main class="main" id="elements">
+		<main class="main" id="elements" contenteditable="true">
 			<div class="heading">Headings</div>
 			<div class="items">
 				<h1>Heading 1</h1>