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HTML

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CSS

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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

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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 

              
                <div id="fixed">
<div id="container">
  <h1>You guys go on without me! I'm going to go… look for more stuff to steal!</h1>
<p>Well I'da done better, but it's plum hard pleading a case while awaiting trial for that there incompetence. You know, I was God once. Shinier than yours, meatbag. You know the worst thing about being a slave? They make you work, but they don't pay you or let you go.</p>
<p>I was having the most wonderful dream. Except you were there, and you were there, and you were there! <strong> That's not soon enough!</strong> <em> Ow, my spirit!</em> Fry, you can't just sit here in the dark listening to classical music.</p>
<h2>Why did you bring us here?</h2>
<p>I love you, buddy! Is that a cooking show? Large bet on myself in round one. When the lights go out, it's nobody's business what goes on between two consenting adults. I'll get my kit!</p>
<ol>
<li>When will that be?</li><li>Goodbye, cruel world. Goodbye, cruel lamp. Goodbye, cruel velvet drapes, lined with what would appear to be some sort of cruel muslin and the cute little pom-pom curtain pull cords. Cruel though they may be…</li><li>Fry! Quit doing the right thing, you jerk!</li>
  <div id="element-c">Element c
    <div id="element">Element</div>
    </div>
</ol>
</div>
</div>
!

CSS 

              
                #container {
  background: yellow;
      
  overflow-wrap: break-word;
    word-wrap: break-word;
    hyphens: auto;
    overflow: hidden;
    overflow-y: auto;
      max-width: 400px;
  max-height: 300px;
}

#element {
  background: blue;
  color: #fff;
  position: absolute;
  min-height: 100px;
  min-width: 100px;
  left: 0;
  top: 280px;
  transform: translateX(0);
}

#element-c {
  padding: 1em;
  background: red;
  position: relative;
}

#fixed {
  position: fixed;
  padding: 2px;
  background: red;
}
!

JS
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999px

Console