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HTML

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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.

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Adding Classes

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About the <head>

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Insecure Resource

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CSS

About CSS Preprocessors

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

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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

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JavaScript

About JavaScript Preprocessors

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

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Babel includes JSX processing.

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

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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.

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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.

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HTML 

              
                .switch
  .quality>
    %input{:id=>"q1",:type=>"radio",:name=>"q",:value=>"q1",:checked=>true}
    %label{:for=>"q1"}720p
  .quality
    %input{:id=>"q2",:type=>"radio",:name=>"q",:value=>"q2"}
    %label{:for=>"q2"}1080p
!

CSS 

              
                @import compass

html
  font-family: 'Gudea', Helvetica, sans-serif
  height: 100%

body
  background-color: #111

.switch
  position: relative
  margin: 100px auto
  width: 180px
  height: 40px
  border: 3px solid #45f
  color: #45f
  font-size: 25px
  border-radius: 10px

.quality
  position: relative
  display: inline-block
  width: 50%
  height: 100%
  line-height: 40px
  &:first-child
    label
      border-radius: 5px 0 0 5px
  &:last-child
    label
      border-radius: 0 5px 5px 0
  label
    position: absolute
    top: 0
    left: 0
    width: 100%
    height: 100%
    cursor: pointer
    font-style: italic
    text-align: center
    transition: transform 0.4s, color 0.4s, background-color 0.4s
  input[type="radio"]
    appearance: none
    width: 0
    height: 0
    opacity: 0
    &:focus 
      outline: 0
      outline-offset: 0
    &:checked ~ label
      background-color: #45f
      color: #111
    &:active ~ label
      transform: scale(1.05)
!

JS
!
999px

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