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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.

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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-.

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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

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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HTML 

              
                <article>
  <h1>Fancy Blockquote Style</h1>
  <p>Spaceflights cannot be stopped. This is not the work of any one man or even a group of men. It is a historical process which mankind is carrying out in accordance with the natural laws of human development.</p>

  <blockquote><p>I believe every human has a finite number of heartbeats. I don't intend to waste any of mine.</p></blockquote>

  <p>The regret on our side is, they used to say years ago, we are reading about you in science class. Now they say, we are reading about you in history class.</p>

  <p>Science has not yet mastered prophecy. We predict too much for the next year and yet far too little for the next 10.</p>
</article>
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CSS 

              
                @import url(https://fonts.googleapis.com/css?family=Droid+Serif:400,700);

body {
  padding: 25px;
  font-family: 'Droid Serif', serif;
  background: #4F7482;
  @media screen and (min-width: 750px) {
    padding: 50px;
  }
}

article {
  margin: 0 auto;
  background: #fff;
  max-width: 600px;
  border-radius: 3px;
  padding: 36px 50px;
  box-shadow: 0 2px rgba(0,0,0,.25);
  h1 {
    margin-top: 0;
    font-size: 2em;
    color: #4F7482;
    font-weight: 700;
    padding-bottom: .2em;
    border-bottom: 1px solid #c2c2c2;
  }
  p {
    font-size: 18px;
    line-height: 1.5em;
    margin-bottom: 28px;
  }
  blockquote {
    width: 100%;
    margin-left: -50px;
    padding: 36px 50px;
    position: relative;
    background: #c2c2c2;
    margin-bottom: 28px;
    &::before, &::after {
      top: 0;
      bottom: 0;
      width: 25px;
      content: '';
      position: absolute;
      background: #c2c2c2;
      box-shadow: 0 2px rgba(0,0,0,.25);
    }
    &::before {
      right: 100%;
    }
    &::after {
      left: 100%;
    }
    p {
      margin: 0;
      font-size: 1.5em;
      &::before {
        top: 0;
        left: 16px;
        color: #fff;
        content: '“';
        font-size: 3em;
        position: absolute;
        text-shadow: -3px 0 #c2c2c2;
      }
      &::after {
        right: 16px;
        color: #fff;
        content: '”';
        bottom: -32px;
        font-size: 3em;
        position: absolute;
        text-shadow: 3px 0 #c2c2c2;
      }
    }
  }
  
  @media screen and (min-width: 750px) {
    h1 {
      font-size: 3em;
    }
    blockquote {
      padding-right: 0;
      width: calc(100% + 50px);
      &::before {
        display: none;
      }
      &::after {
        width: 50px;
        border-radius: 0 3px 3px 0;
      }
      p {
        font-size: 2.5em;
        &::after {
          bottom: -56px
        }
      }
    }
  }
}
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JS
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