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.

+ add another resource


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.

+ add another resource


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.


  svg[style="max-height:100%" overflow="visible" fill="currentcolor"]
    text[y="50%" font-family="inherit" font-weight="inherit"] A responsive one-line header
p This header maintains its default font-size until it is too wide to fit on the page. If it starts overflowing, it will adjust to take up 100% of the page width.

  | Resize the page to try it out! Inspired by 
  a href="" Fitter Happier Text
  | .



                $color: #333

html, body, svg, text
  width: 100%

body, a
  color: $color
  margin: 0
  padding: 24px
  font-size: 22px
  max-width: 540px
  text-align: justify
  box-sizing: border-box
  margin: 36px 0 0  
  font: bold 1rem sans-serif
  border-bottom: 2px solid $color
  max-width: 360px



                const svg = document.querySelector('svg');
const {width, height} = svg.querySelector('text').getBBox();

svg.setAttribute('viewBox', `0 0 ${width} ${height}`);