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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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Adding Classes

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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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HTML 

              
                <body>
  <script>
    document.body.classList.add('fade');
    document.addEventListener('DOMContentLoaded', () => {
      window.setTimeout(function() {
        document.body.classList.remove('fade');
      }, 230);
    });
  </script>
  <div class="bg__color-1 padding-50 text-justify">
    <h1>Lorem ipsum dolor sit amet.</h1>
    <p>
      Lorem ipsum, dolor sit amet consectetur adipisicing elit. Eveniet porro
      ullam, tempore quaerat sit nobis sapiente fugit. Iure optio quis
      delectus culpa, blanditiis hic aliquid eligendi nesciunt quo neque
      inventore. Dolor, quas, repudiandae optio minus voluptas ea earum,
      minima similique omnis officiis magni rem voluptates? Ex, odio iusto
      deleniti quo quae maiores earum dolorem, optio incidunt impedit
      laudantium non magnam. Quia itaque eum facilis quae voluptate tempore!
      Laudantium quidem debitis architecto suscipit aut nesciunt officiis non
      soluta quo numquam hic iure natus doloremque rem, recusandae.
    </p>
    <a href="fade-in-1.html" class="link">Go to previous page</a>
  </div>
  <div class="bg__color-2 padding-50 text-justify">
    <h1>Lorem ipsum dolor sit amet.</h1>
    <p>
      Lorem ipsum, dolor sit amet consectetur adipisicing elit. Eveniet porro
      ullam, tempore quaerat sit nobis sapiente fugit. Iure optio quis
      delectus culpa, blanditiis hic aliquid eligendi nesciunt quo neque
      inventore. Dolor, quas, repudiandae optio minus voluptas ea earum,
      minima similique omnis officiis magni rem voluptates? Ex, odio iusto
      deleniti quo quae maiores earum dolorem, optio incidunt impedit
      laudantium non magnam. Quia itaque eum facilis quae voluptate tempore!
      Laudantium quidem debitis architecto suscipit aut nesciunt officiis non
      soluta quo numquam hic iure natus doloremque rem, recusandae.
    </p>
  </div>
  <div class="bg__color-3 padding-50 text-justify">
    <h1>Lorem ipsum dolor sit amet.</h1>
    <p>
      Lorem ipsum, dolor sit amet consectetur adipisicing elit. Eveniet porro
      ullam, tempore quaerat sit nobis sapiente fugit. Iure optio quis
      delectus culpa, blanditiis hic aliquid eligendi nesciunt quo neque
      inventore. Dolor, quas, repudiandae optio minus voluptas ea earum,
      minima similique omnis officiis magni rem voluptates? Ex, odio iusto
      deleniti quo quae maiores earum dolorem, optio incidunt impedit
      laudantium non magnam. Quia itaque eum facilis quae voluptate tempore!
      Laudantium quidem debitis architecto suscipit aut nesciunt officiis non
      soluta quo numquam hic iure natus doloremque rem, recusandae.
    </p>
  </div>
  <div class="bg__color-4 padding-50 text-justify">
    <h1>Lorem ipsum dolor sit amet.</h1>
    <p>
      Lorem ipsum, dolor sit amet consectetur adipisicing elit. Eveniet porro
      ullam, tempore quaerat sit nobis sapiente fugit. Iure optio quis
      delectus culpa, blanditiis hic aliquid eligendi nesciunt quo neque
      inventore. Dolor, quas, repudiandae optio minus voluptas ea earum,
      minima similique omnis officiis magni rem voluptates? Ex, odio iusto
      deleniti quo quae maiores earum dolorem, optio incidunt impedit
      laudantium non magnam. Quia itaque eum facilis quae voluptate tempore!
      Laudantium quidem debitis architecto suscipit aut nesciunt officiis non
      soluta quo numquam hic iure natus doloremque rem, recusandae.
    </p>
  </div>
</body>
!

CSS 

              
                @import url("https://fonts.googleapis.com/css2?family=Kaisei+Decol:wght@400;500&display=swap");

body {
  font-family: "Kaisei Decol", serif;
  opacity: 1;
  transition-duration: 0.7s;
  transition-property: opacity;
}

body.fade {
  opacity: 0;
}

.padding-50 {
  padding: 50px;
}

.text-justify {
  text-align: justify;
}

.bg__color-1 {
  background-color: #e8d0b3;
}

.bg__color-2 {
  background-color: #c36839;
}

.bg__color-3 {
  background-color: #7eb5a6;
}

.bg__color-4 {
  background-color: #86340a;
}

.link {
  text-decoration: none;
  font-family: inherit;
  font-size: 14px;
  color: #222222;
  font-weight: bold;
}
!

JS
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999px

Console