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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.

Add External Scripts/Pens

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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.

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.

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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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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.

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HTML 

              
                -var elSet = 5
.bar
	-for(var n = 0; n < elSet; n++)
		input.bar-input(
			type="radio"
			name="input"
			id="input_" + n
		)
		.bar-view
			label.bar-button(
				for="input_" + n
			)
			
.command click on any one of the options
!

CSS 

              
                $elSet: 5
$elCount: $elSet * 2
$orange: #FE9000
$orange-light: #FFB732
$yellow: #FFDD4A
$blue-light: #5ADBFF
$blue: #3C6997
$bounce: cubic-bezier(0, 0, 0, 1.97)
$smooth: cubic-bezier(0, 0.72, 0.58, 1)

.bar
	display: flex
	flex-direction: row-reverse
	margin: auto auto 0
	width: 300px
	max-width: calc(100% - 30px)

	&-input
		opacity: 0
		pointer-events: none
		position: absolute
		top: -9999px
		left: -9999px
	
		&:checked
			~ .bar-view
					@for $n from 1 through $elCount
						$r: $elCount - $n + 1
						@if $r % 2 == 0
							&:nth-child(#{$r})
								&:after
									transition-delay: 0.1s * ($n / 2 - 1)
								.bar-button:before
									transition-delay: 0.1s * ($n / 2 - 1) + 0.06s
								
					&:after
						transform: scaleX(1)
					.bar-button:before
						transform: none
						opacity: 1
			
			+ .bar-view
					.bar-button:after
						opacity: 1
						animation: bouncing 0.6s cubic-bezier(0, 0, 0.74, 1.04) infinite
	
	&-view
		display: flex
		flex-grow: 1
		position: relative
	
		&:after
			height: 2px
			top: calc(50% - 1px)
			transition: transform 0.06s $smooth
			transform: scaleX(0)
			background: $orange-light
			transform-origin: left
			z-index: 1
	
		&:not(:last-child)
			&:before,
			&:after
				content: ''
				width: calc(100% - 24px)
				position: absolute
				right: calc(50% + 12px)

			&:before
				height: 6px
				top: calc(50% - 3px)
				background: $blue
	
			@for $n from 1 through $elCount
				@if $n % 2 == 0
					&:nth-child(#{$n})
						&:after
							transition-delay: 0.1s * ($n / 2 - 1)
						.bar-button:before
							transition-delay: 0.1s * ($n / 2 - 1) + 0.06s
	
	&-button
		display: block
		width: 30px
		height: 30px
		margin: auto
		border-radius: 50%
		border: 3px solid $blue
		position: relative
		cursor: pointer
		box-shadow: inset 2px 2px 4px rgba(0, 0, 0, 0.3), 2px 2px 8px rgba(0, 0, 0, 0.1)
	
		&:hover:after
			transform: none
			opacity: 1
	
		&:before,
		&:after
			content: ''
			position: absolute
			pointer-events: none
	
		&:before
			width: 100%
			height: 100%
			border-radius: 50%
			background: radial-gradient(circle at center, $yellow, $orange)	
			transform: scale(0.3)
			opacity: 0
			transition:
				property: transform, opacity
				duration: 0.2s
				timing-function: $smooth
		
		&:after
			border: 8px solid transparent
			border-top-color: $blue-light
			bottom: calc(100% + 10px)
			left: calc(50% - 8px)
			transform: translateY(-10px)
			opacity: 0
			transition:
				property: transform, opacity
				duration: 0.2s
				timing-function: $bounce

.command
	font-family: 'Ubuntu Mono', monospace
	letter-spacing: 1px
	margin: 30px auto auto
	animation: fade 1s ease infinite

html, body
	width: 100%
	height: 100%
	display: flex
	flex-direction: column
	background: linear-gradient(to bottom right, transparentize($yellow, 0.9), #fff)

*
	box-sizing: border-box
	&:before, &:after
		box-sizing: inherit

@keyframes bouncing
	0%, 100%
		transform: translateY(0)
	50%
		transform: translateY(5px)

@keyframes fade
	50%
		opacity: 0.3
!

JS 

              
                /*
	no JS >|
*/
!
999px

Console