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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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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

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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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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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HTML 

              
                <h2>Default</h2>
<p>
  <strong>(`display: block; color: red; padding: 0;`)</strong> 
  Lorem ipsum dolor sit amet consectetur adipisicing elit. Nisi, amet officiis. Quam accusantium voluptates nobis commodi eos, ducimus iste harum quos illum? Accusantium beatae dignissimos adipisci eos in maiores iusto!
</p>
<p>Lorem ipsum, dolor sit amet consectetur adipisicing elit. Repellendus nobis, vero odit, maxime possimus repudiandae cum aperiam facere provident vel nesciunt qui quidem iusto. Quibusdam illo impedit odio vero et.</p>

<h2>Inherit</h2>
<p class="inherit">
  <strong>`Inherit` uses the same value as the parent element (`display: block; color: red; padding: 2em;`)</strong>
  Lorem ipsum dolor sit amet consectetur adipisicing elit. Voluptatibus ex cupiditate consequatur, in voluptates debitis dolor placeat quis fugit, perferendis provident necessitatibus ad veniam quia dignissimos ut, esse eveniet commodi?
</p>
<p class="inherit">
  Lorem ipsum dolor sit, amet consectetur adipisicing elit. Dolorum corrupti eum laborum fugiat, perferendis sed ullam animi consequuntur placeat, incidunt tempora officiis reiciendis vel distinctio voluptas eaque mollitia reprehenderit aut!
</p>

<h2>Initial</h2>
<p class="initial">
  <strong>`Initial` resets all properties to their spec default (`display: inline; color: black; padding: 0;`)</strong>
  Lorem ipsum dolor sit amet consectetur adipisicing elit. Voluptatibus ex cupiditate consequatur, in voluptates debitis dolor placeat quis fugit, perferendis provident necessitatibus ad veniam quia dignissimos ut, esse eveniet commodi?
</p>
<p class="initial">
  Lorem ipsum dolor sit amet, consectetur adipisicing elit. Perspiciatis, reiciendis aperiam quis voluptas magni culpa? Facere quae vel dolore deleniti delectus labore unde autem sunt suscipit aut. Officiis, iusto corrupti.
</p>

<h2>Unset</h2>
<p class="unset">
  <strong>`Unset` allows default inheritance (color, but not padding), then falls back on the `initial` value (`display: inline; color: red; padding: 0;`)</strong>
  Lorem ipsum dolor sit amet consectetur, adipisicing elit. Eaque exercitationem cum vitae aperiam quod adipisci, distinctio ullam dicta ad veritatis quibusdam animi sunt, laboriosam et placeat, quam enim neque maxime.
</p>
<p>
  Lorem ipsum dolor sit amet consectetur adipisicing elit. Excepturi in hic temporibus autem tempore, nulla similique rerum adipisci, alias ea laborum, fuga sed unde atque molestiae necessitatibus officia maxime magnam!
</p>

<h2>Revert</h2>
<p class="revert">
  <strong>`Revert` allows default inheritance (color, but not padding), then falls back on user/user-agent values (`display: block; color: red; padding: 0;`)</strong>
  Lorem, ipsum dolor sit amet consectetur adipisicing elit. Quia, laboriosam, omnis ad explicabo optio ipsum ipsam ut temporibus magnam officiis minus rem, quisquam soluta quibusdam enim quidem dolore quod. Eius!
</p>
<p>
  Lorem ipsum dolor sit amet consectetur adipisicing elit. Laboriosam, adipisci quae molestias saepe officia odit corrupti maiores impedit accusamus placeat reprehenderit. Alias, laborum! Consequatur itaque illum dignissimos repellendus ut recusandae.
</p>
!

CSS 

              
                body {
  background: white;
  color: rebeccapurple;
  padding: 2em;
}

/* visualization help */
p { outline: 1px dotted blue; }

.inherit {
  display: inherit;
  color: inherit;
  padding: inherit;
}

.initial {
  display: initial;
  color: initial;
  padding: initial;
}

.unset {
  display: unset;
  color: unset;
  padding: unset;
}

.revert {
  display: revert;
  color: revert;
  padding: revert;
}






/* style */
body {
  margin: 1em auto;
  max-width: 45em;
}
!

JS
!
999px

Console