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

If active, Pens will autosave every 30 seconds after being saved once.

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

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.


                <div class="intro">
  Side colums have fixed width, Main column is flexible.
<div class="parent">
  <div class="child left">Left</div>
  <div class="child main">Main</div>
  <div class="child right">Right</div>


  margin: 0
  padding: 0
  font-family: sans-serif

  padding: 10px
  text-align: center
  padding: 20px 10px
  box-sizing: border-box

  display: flex
  width: 150px
  flex: 0 0 auto
  background-color: tomato
  flex: 1 0 auto
  background-color: #eee
  min-height: 500px
  width: 80px
  flex: 0 0 auto
  background-color: #ddd