Pen Settings

HTML

About HTML Preprocessors

HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

Learn more · Versions

Adding Classes

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

!
Insecure Resource

The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.

CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

Learn more · Versions

CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

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.

Powered by Algolia
About External Resources

You can apply CSS to your Pen from any stylesheet on the web. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself.

You can also link to another Pen here (use the .css URL Extension) and we'll pull the CSS from that Pen and include it. If it's using a matching preprocessor, use the appropriate URL Extension and we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

Learn more

+ add another resource

JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

Learn more · Versions

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.

Powered by Algolia
About External Resources

You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

Learn more

+ 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.

Powered by Algolia
About Packages

Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.

All packages are different, so refer to their docs for how they work.

If you're using React / ReactDOM, make sure to turn on Babel for the JSX processing.

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 

              
                .frame
  .lines
  .angles
  article
    p Hover me
!

CSS 

              
                $ease-in-out-quad = cubic-bezier(0.455, 0.03, 0.515, 0.955)
$color-grey = #A6AFC0
$color-off-white = #34495E

body
  background-color #2c3e50
  margin 0
  padding 0
  width 100%
  height 100%

  .frame
    display inline-block
    position absolute
    top 50%
    left 50%
    transform translate(-50%, -50%)

  // THE MAGIC STARTS HERE
  .lines
    background:
      linear-gradient(to bottom, $color-off-white 2px, transparent 2px) 0 0, // TOP LEFT TO TOP RIGHT
      linear-gradient(to right, $color-off-white 2px, transparent 2px) 0 100%, // BOTTOM LEFT TO TOP LEFT
      linear-gradient(to left, $color-off-white 2px, transparent 2px) 100% 0, // TOP RIGHT TO BOTTOM RIGHT
      linear-gradient(to top, $color-off-white 2px, transparent 2px) 100% 100%; // BOTTOM RIGHT TO TOP RIGHT
    background-repeat no-repeat
    background-size 0px 0px
    position absolute
    top 0
    right 0
    bottom 0
    left 0
    transition background-size 0.2s $ease-in-out-quad

  .angles
    background:
      linear-gradient(to right, $color-grey 2px, transparent 2px) 0 0, // TOP LEFT
      linear-gradient(to bottom, $color-grey 2px, transparent 2px) 0 0, // TOP LEFT
      linear-gradient(to left, $color-grey 2px, transparent 2px) 100% 0, // TOP RIGHT
      linear-gradient(to bottom, $color-grey 2px, transparent 2px) 100% 0, // TOP RIGHT
      linear-gradient(to left, $color-grey 2px, transparent 2px) 100% 100%, // BOTTOM RIGHT
      linear-gradient(to top, $color-grey 2px, transparent 2px) 100% 100%, // BOTTOM RIGHT
      linear-gradient(to right, $color-grey 2px, transparent 2px) 0 100%, // BOTTOM LEFT
      linear-gradient(to top, $color-grey 2px, transparent 2px) 0 100%; // BOTTOM LEFT
    background-repeat no-repeat
    background-size 7px 7px
    position absolute
    top 0
    right 0
    bottom 0
    left 0
    opacity 0.48
    transition background-size 0.2s $ease-in-out-quad

  &:hover
    .lines
      background-size 100% 100%

    .angles
      background-size 14px 14px
  // THE MAGIC ENDS HERE

  article
    padding 13px
    display flex
    justify-content center
    align-items center
    width 500px
    height 400px
    position relative
    cursor pointer

    &:before
      content ''
      background-color rgba(#FFFFFF, 0.08)
      opacity 0.46
      position absolute
      top 13px
      right 13px
      bottom 13px
      left 13px
      transition all 0.2s $ease-in-out-quad

    &:hover:before
      top 21px
      right 21px
      bottom 21px
      left 21px

  p
    font-family sans-serif
    font-size 14px
    text-transform uppercase
    color #FFFFFF
    position relative
!

JS
!
999px

Console