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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.

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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

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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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HTML 

              
                <div class="background"></div>

<div class="section">
	<div class="section__img">
		<div class="section__img__inner" style="background-image: url(http://media.idownloadblog.com/wp-content/uploads/2014/10/iPad-mini-3-silver-side-by-side.png);"></div>
	</div>
	<div class="section__body">
			<div class="section__text">
			<h2>Section title</h2>
			<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
		</div>
	</div>
</div>

<div class="section">
	<div class="section__img">
		<div class="section__img__inner" style="background-image: url(http://wpuploads.appadvice.com/wp-content/uploads/2014/12/ipad-c4a63aad52bb1d69495bc2100e5f2026.png);"></div>
	</div>
	<div class="section__body">
			<div class="section__text">
			<h2>Section title</h2>
			<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
				<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
				<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
				<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
		</div>
	</div>
</div>

<div class="section">
	<div class="section__img">
		<div class="section__img__inner" style="background-image: url(http://www.consult-pro.com/img/dental-videos-ipad-app.png);"></div>
	</div>
	<div class="section__body">
			<div class="section__text">
			<h2>Section title</h2>
			<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
		</div>
	</div>
</div>

<div class="section">
	<div class="section__img">
		<div class="section__img__inner" style="background-image: url(https://fortunedotcom.files.wordpress.com/2014/11/apple-ipad-air2-apps_large.png?w=1024);"></div>
	</div>
	<div class="section__body">
		<div class="section__text">
			<h2>Section title</h2>
			<p>Sed dapibus ornare risus vel vehicula. Nunc elit lacus, lacinia vel molestie et, lacinia non augue. Aenean quis iaculis velit. Sed aliquet semper metus quis egestas. Nullam lorem turpis, euismod nec feugiat at, venenatis quis odio. Aenean tellus libero, rutrum in mauris in, suscipit aliquam lacus. Proin ac viverra risus. Vivamus ullamcorper, massa id congue sagittis, erat ipsum aliquet tellus, nec sollicitudin erat risus vitae nisl.</p>
			<p>Nunc viverra mollis quam sit amet tristique. Phasellus gravida ipsum ac felis commodo, vitae bibendum lacus fermentum. Nam id imperdiet turpis. Aliquam ut gravida tellus, ut accumsan libero. Praesent nec imperdiet nibh. Integer dui turpis, vestibulum in finibus eget, elementum ut eros. Nullam malesuada lectus ut ex malesuada volutpat. Sed id ligula euismod, egestas nulla nec, mattis purus. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p>
		</div>
	</div>
</div>
!

CSS 

              
                html {
	line-height: 1.618;
}

.background {
	background-color: #ffcd03;
	position: fixed;
	top: 0;
	left: 0;
	width: 50%;
	height: 100vh;
	z-index: 1;
}

.section {
	display: flex;
	min-height: 100vh;
	position: relative;
	z-index: 2;
	
	> * {
		width: 50%;
	}
	
	&__img {
		position: relative;
		display: flex;
		
		&__inner {
			height: 100vh;
			position: fixed;
			left: 5%;
			width: 40%;
			top: 0;
			mix-blend-mode: multiply;
			background-size: contain;
			background-repeat: no-repeat;
			background-position: 50% 50%;
		}
	}
	
	&__body {
		display: flex;
		align-items: center;
		position: relative;
		z-index: 100;
	}
	
	&__text {
		padding: 5vw;
	}
}


.section__img__inner {
	filter: blur(30px);
	opacity: 0;
	background-position: 50% 40%;
	transition: filter .6s ease, opacity .6s ease, background-position 0.8s ease;
}

.section.active .section__img__inner {
	opacity: 1;
	background-position: 50% 50%;
	filter: blur(0);
}

h2 {
	font-size: 3vw;
	margin-bottom: 0.5em;
	margin-top: 0;
}
!

JS 

              
                $(window).scroll(function() {
  
  // selectors
  var $window = $(window),
      $body = $('body'),
      $panel = $('.section');
  
  // Change 33% earlier than scroll position so colour is there when you arrive.
  var scroll = $window.scrollTop() + ($window.height() / 3);
 
	$('.section').removeClass('active');
	
  $panel.each(function () {
    var $this = $(this);
    
    // if position is within range of this panel.
    // So position of (position of top of div <= scroll position) && (position of bottom of div > scroll position).
    // Remember we set the scroll to 33% earlier in scroll var.
    if ($this.position().top <= scroll && $this.position().top + $this.height() > scroll) {
      $this.addClass('active');

    }
  });    
  
}).scroll();
!
999px

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