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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.

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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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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.

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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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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 

              
                <h1>Variables en CSS</h1>
<p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Necessitatibus enim quibusdam dolore quasi numquam ratione. Autem sint necessitatibus quam. Minus veritatis maiores officia quia hic provident necessitatibus eveniet reprehenderit ipsam.</p>
<p>Enim incidunt esse quis earum voluptates nihil fuga nostrum? Perspiciatis facilis quaerat adipisci officiis corrupti vitae quos aspernatur sapiente ducimus? Ipsam fugit, eligendi et ea labore ut quod voluptates est.</p>
<p>Quas eos, iure praesentium aliquid porro facilis maxime. Excepturi suscipit optio, ducimus totam odio, nisi quidem cum earum accusamus sed minima? Tempora corrupti aliquid maxime deserunt esse aspernatur omnis consectetur.</p>
<p>Sapiente, ipsum veniam culpa assumenda fugit doloremque rem! Architecto optio neque quidem praesentium animi molestias voluptate commodi iste cumque minus, accusamus distinctio autem possimus, quisquam, corrupti tempore voluptatem quia? Expedita?</p>
<p>Autem, ullam voluptate. Dolores corporis, ex enim repellat nihil molestiae cum harum! Aliquam id accusantium cupiditate, facere eum officiis culpa, soluta illum consequatur molestiae a vitae ut amet exercitationem corporis!</p>
<p>Vitae dignissimos ullam quae maxime illum, aliquam ipsa ab voluptate delectus, error laudantium et quisquam perferendis doloremque. Ullam nisi aspernatur aliquid? Doloremque recusandae libero obcaecati, facere sit reiciendis et sint.</p>
<p>Consequuntur a vel, aspernatur exercitationem, repellat laudantium est officiis, iusto accusamus expedita amet fugiat necessitatibus vero voluptatem quas maxime quisquam velit. Corporis ea vel qui eius non, quasi perferendis est?</p>
<p>Pariatur sapiente suscipit ut nam temporibus debitis aspernatur, non at perferendis, cupiditate vitae! Earum ipsam, quas perferendis voluptatum tenetur, debitis dolor quidem sed consequatur repudiandae possimus magnam eos itaque? Omnis.</p>
<p>Doloremque a facilis consequatur? Rerum ea mollitia quasi voluptatibus alias aspernatur sint quae ullam autem. Nobis hic nemo ratione dolorum perferendis soluta, quas quam tempore deserunt, repellat, consectetur laboriosam voluptatem!</p>
<p>Reprehenderit excepturi totam iusto veritatis provident rerum blanditiis non architecto vel quibusdam iure debitis nihil, consectetur quos dolorum, voluptatum praesentium explicabo. Quas, ratione. Necessitatibus dolorem id doloribus quisquam iure magnam.</p>
<p>Inventore delectus sed perspiciatis. Hic ullam quaerat deleniti cupiditate exercitationem, eum doloribus inventore illo recusandae quia excepturi nostrum. Quaerat eos doloremque ad sit, itaque maiores debitis molestias eum dolorum placeat.</p>
<p>Velit autem, illo ratione quae iusto doloribus iure, impedit animi recusandae ducimus rerum officiis voluptatibus totam, dolorum at necessitatibus et deleniti qui laboriosam. Et optio explicabo consequuntur molestiae similique consectetur.</p>
<p>Distinctio optio molestiae, blanditiis doloribus deserunt a aspernatur modi odit obcaecati nesciunt molestias hic praesentium eius ullam eaque architecto quae vel nihil? Dolore quia eius consequatur suscipit illo quaerat ipsa.</p>
<p>Dolore at incidunt perferendis ipsum corporis ut, facilis magnam repellendus aliquam commodi dolorem officia. Reiciendis, harum officiis velit at natus earum esse. Esse id a aspernatur. Voluptates ab eveniet sit!</p>
<p>Quas sequi ducimus vero nemo totam hic ratione, veritatis deserunt eaque molestiae reprehenderit ab exercitationem nihil aspernatur sit fugiat laboriosam ipsam. Dolorum quidem voluptate totam, doloremque ipsum laborum dolor? Delectus.</p>
<p>Tempora voluptatibus, ex ipsa ratione dolorum saepe molestias maiores accusamus eum iusto laudantium deleniti ut rerum fugiat sapiente facilis harum est odio doloribus eius earum quasi vitae commodi fuga? Tempore.</p>
<p>Placeat totam tempore itaque recusandae. Fugiat rem consequatur facilis, distinctio cum nostrum magnam doloremque voluptate porro! Ipsam, in! Quo placeat pariatur ea ut tempore alias quisquam molestiae exercitationem architecto voluptas.</p>
<p>Molestiae aut eaque ipsam, magnam consequuntur eos, distinctio iste quis perspiciatis delectus libero nostrum. Totam doloribus placeat ipsum quos obcaecati! Nam, blanditiis suscipit culpa deserunt numquam incidunt inventore impedit expedita.</p>
<p>Nisi, ea distinctio pariatur, rerum ducimus blanditiis dicta reprehenderit nostrum libero atque quis saepe officiis quisquam alias autem doloribus debitis et iure dolore veniam nobis beatae ratione ullam? Iste, deserunt?</p>
<p>Error ratione pariatur reiciendis, corrupti eius sit cumque nesciunt fuga aut qui, autem, officia distinctio fugit odit minima eaque voluptate nulla eum tenetur quod architecto! Alias harum debitis impedit nihil!</p>
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CSS 

              
                :root {
  --b: #1888F6;
  --c: #1F4787;
  --text: 28px;
  --title: 46px;
}

h1{
  color: var(--b);
  font-size: var(--title);
}

p{
  color: var(--c);
  font-size: var(--text);
}
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JS
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999px

Console