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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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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-.

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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

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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 Skypack, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ES6 import usage.

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

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HTML 

              
                #app
	#toolbar
		#traffic-light
			.aqua#red
			.aqua#yellow
			.aqua#green
	#view
		#tree
			%ul
				%li index.haml
				%li style.sass
		#textfield
			%pre
				:preserve
					/* Cocoa code editor in SASS and HAML */

					.someclass {
						width: 100px;
						height: 100px;
					}

					#someID {
						color: red;
						position: absolute;
					}
					#ldq {padding:0;}
	#statusbar
!

CSS 

              
                @import compass

html
  display: table
  width: 100%
  height: 100%

body
  margin: 0px
  padding: 50px
  display: table-cell
  vertical-align: middle
  font-family: "Lucida Grande"
  font-size: 12px
  +background(linear-gradient(top left, #33799d, #e8ebb4))

ul
  margin: 0
  padding: 0
  li
    margin: 2px

#app
  display: block
  width: 482px
  height: 384px
  margin: 0 auto
  background-color: #ededed
  +box-shadow(rgba(#000, .1) 1px 1px, rgba(#000, .1) -1px -1px, rgba(#000, .1) 1px -1px, rgba(#000, .1) -1px 1px, rgba(#000, .8) 0 0 70px)
  +border-radius(5px)

#toolbar
  height: 21px
  display: block
  border-bottom: solid 1px #686868
  +background(linear-gradient(#e4e4e4, #b8b7b8))
  +box-shadow(#f1f1f1 0 1px inset)
  +border-radius(6px 6px 0 0)

#traffic-light
  display: inline
  margin-left: 4px
  float: left
  .aqua
    width: 12px
    height: 12px
    display: block
    margin: 5px 4px 4px 4px
    background: #000
    float: left
    +background-image(radial-gradient(6px 18px, rgba(#fff, .7) 2px, rgba(#fff, 0) 5px), radial-gradient(6px -1px, #fff 1px, rgba(#fff, 0) 3px))
    +box-shadow(rgba(#000, .9) 0 1px 4px inset, rgba(#fff, .5) 0 1px)
    +border-radius(100px)
    &#red
      background-color: #f24443
    &#yellow
      background-color: #f0aa5a
    &#green
      background-color: #88be72

#view
  width: 482px
  height: 340px
  *
    +float-left

#tree
  width: 80px
  height: 320px
  padding: 10px
  color: #455563
  background-color: #e6eaef
  +box-shadow(#bdbdbd -1px 0 inset)

#textfield
  width: 362px
  height: 340px
  padding: 0 10px
  color: #a7a7a7
  background-color: #222222

#statusbar
  height: 21px
  display: block
  border-top: solid 1px #686868
  +background(linear-gradient(#e4e4e4, #b8b7b8))
  +box-shadow(#f1f1f1 0 1px inset)
  +border-radius(0 0 4px 4px)
  +clearfix
!

JS
!
999px

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