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.


Save Automatically?

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.


                button Boo!


  display flex
  align-items center
  justify-content center
  min-height 100vh
  background #fafafa
  color #fafafa
  border 5px solid red
  background transparent
  color red
  padding 8px 16px
  font-weight bold
  font-size 3rem
  cursor pointer
  outline transparent
  transition background .25s ease, color .25s ease, box-shadow .15s ease
  box-shadow 8px 8px 0 #888
    color currentColor
    background red
    box-shadow 4px 4px 0 #888
    box-shadow 0 0 0 #888