Pen Settings

HTML

CSS

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

JavaScript

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

Packages

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.

Behavior

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.

HTML

              
                <article>
  <h1>Accessible footnotes with CSS</h1>

  <p>Maintaining <a href="#footnotes" aria-describedby="footnote-label" id="footnotes-ref">footnotes</a> manually can be a pain. By using <a href="#css" aria-describedby="footnote-label" id="css-ref">CSS</a> <a href="#css-counters" aria-describedby="footnote-label" id="css-counters-ref">counters</a> to add the numbered references in the text and an ordered list to display the actual footnotes in the footer, it becomes extremely easy.</p>

  <footer>
    <h2 class="visually-hidden" id="footnote-label">Footnotes</h2>
    <ol>
      <li id="footnotes">Footnotes are notes placed at the bottom of a page. They cite references or comment on a designated part of the text above it. <a href="#footnotes-ref" aria-label="Back to content">↩</a></li>
      
      <li id="css">Cascading Style Sheets <a href="#css-ref" aria-label="Back to content">↩</a></li>

      <li id="css-counters">CSS counters are, in essence, variables maintained by CSS whose values may be incremented by CSS rules to track how many times they're used. <a href="#css-counters-ref" aria-label="Back to content">↩</a></li>
    </ol>
  </footer>
</article>
              
            
!

CSS

              
                html {
  box-sizing: border-box;
}

* {
  box-sizing: inherit;
}

body {
  margin: 20px;
  font-size: 125%;
  line-height: 1.4;
  max-width: 600px;
  margin: 0 auto;
}

footer {
  margin-top: 50px;
  border-top: 1px solid silver;
  font-size: 0.8em;
}

footer ol {
  padding-left: 20px;
}

/**
 * Initialiazing a `footnotes` counter on the wrapper
 */
article {
  counter-reset: footnotes;
}

/**
 * Inline footnotes references
 * 1. Increment the counter at each new reference
 * 2. Reset link styles to make it appear like regular text
 */
[aria-describedby="footnote-label"] {
  counter-increment: footnotes; /* 1 */
  text-decoration: none; /* 2 */
  color: inherit; /* 2 */
  cursor: default; /* 2 */
  outline: none; /* 2 */
}

/**
 * Actual numbered references
 * 1. Display the current state of the counter (e.g. `[1]`)
 * 2. Align text as superscript
 * 3. Make the number smaller (since it's superscript)
 * 4. Slightly offset the number from the text
 * 5. Reset link styles on the number to show it's usable
 */
[aria-describedby="footnote-label"]::after {
  content: '[' counter(footnotes) ']'; /* 1 */
  vertical-align: super; /* 2 */
  font-size: 0.5em; /* 3 */
  margin-left: 2px; /* 4 */
  color: blue; /* 5 */
  text-decoration: underline; /* 5 */
  cursor: pointer; /* 5 */
}

/**
 * Resetting the default focused styles on the number
 */
[aria-describedby="footnote-label"]:focus::after {
  outline: thin dotted;
  outline-offset: 2px;
}

[aria-label="Back to content"] {
  font-size: 0.8em;
}

/**
 * Highlight target note
 */
footer :target {
  background: yellow;
}

/**
 * Visually hidden yet accessible content
 */
.visually-hidden {
  position: absolute;
  clip: rect(0 0 0 0);
  visibility: hidden;
  opacity: 0;
}
              
            
!

JS

              
                
              
            
!
999px

Console