Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

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Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

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Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.


Auto Save

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Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

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Visit your global Editor Settings.


                <disclosure-widget label="information about pancakes">
  <h3>Pancakes are the best</h3>
  <p>A pancake is a flat cake, often thin and round, prepared from a starch-based batter that may contain eggs, milk and butter and cooked on a hot surface, often frying with oil or butter.</p>


                /* As well as importing JS, you could also include (one way or other) the CSS for the component too, but if you don’t, you could write custom styles e.g.: */
disclosure-widget {
  display: block;
  max-width: 40ch;
  border: 1px solid red;
  padding: 2em;

/* Some base styles for pen */
:root {
  font-family: system-ui;



                import { DisclosureWidget } from "";