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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

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.

!
Insecure Resource

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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

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 

              
                <div class="progress-bar" role="presentation"></div>

<main>
  <p>Lorem Elsass Ipsum mitt picon bière munster du ftomi! Ponchour bisame. Bibbeleskaas jetz rossbolla sech choucroute un schwanz geburtstàg, Chinette dû, ìch bier deppfele schiesser. Flammekueche de knèkes Seppele gal! a hopla geburtstàg, alles fraü Chulia Roberts oder knäckes dûû blottkopf. Noch bredele schissabibala, yeuh e schmutz. E gewurtztraminer doch Carola schneck, schmutz a riesling de chambon eme rucksack Roger dû hopla geiss, jetz Chorchette de Scharrarbergheim. Kouglopf ech ìch wurscht gueut mitt schneck jetz a schiss mannele, knèkes saucisse de Niederhausbergen of fill mauls schéni fleischwurcht schnaps de eme gal nüdle blottkopf, de Chulien Roger hop pfourtz! bett mer ech schpeck un salami schmutz. Gal!</p>
  <p>Lorem Elsass Ipsum mitt picon bière munster du ftomi! Ponchour bisame. Bibbeleskaas jetz rossbolla sech choucroute un schwanz geburtstàg, Chinette dû, ìch bier deppfele schiesser. Flammekueche de knèkes Seppele gal! a hopla geburtstàg, alles fraü Chulia Roberts oder knäckes dûû blottkopf. Noch bredele schissabibala, yeuh e schmutz. E gewurtztraminer doch Carola schneck, schmutz a riesling de chambon eme rucksack Roger dû hopla geiss, jetz Chorchette de Scharrarbergheim. Kouglopf ech ìch wurscht gueut mitt schneck jetz a schiss mannele, knèkes saucisse de Niederhausbergen of fill mauls schéni fleischwurcht schnaps de eme gal nüdle blottkopf, de Chulien Roger hop pfourtz! bett mer ech schpeck un salami schmutz. Gal!</p>
  <p>Lorem Elsass Ipsum mitt picon bière munster du ftomi! Ponchour bisame. Bibbeleskaas jetz rossbolla sech choucroute un schwanz geburtstàg, Chinette dû, ìch bier deppfele schiesser. Flammekueche de knèkes Seppele gal! a hopla geburtstàg, alles fraü Chulia Roberts oder knäckes dûû blottkopf. Noch bredele schissabibala, yeuh e schmutz. E gewurtztraminer doch Carola schneck, schmutz a riesling de chambon eme rucksack Roger dû hopla geiss, jetz Chorchette de Scharrarbergheim. Kouglopf ech ìch wurscht gueut mitt schneck jetz a schiss mannele, knèkes saucisse de Niederhausbergen of fill mauls schéni fleischwurcht schnaps de eme gal nüdle blottkopf, de Chulien Roger hop pfourtz! bett mer ech schpeck un salami schmutz. Gal!</p>
</main>
!

CSS 

              
                .progress-bar {
  --progress-color: hotpink;
  --progress-size: 40px;
  position: fixed;
  top: 0;
  width: 100%;
  height: var(--progress-size);
  background: var(--progress-color);
  transform-origin: left;
}

@supports (animation-timeline: scroll()) {
  .progress-bar {
    animation: scale linear auto both;
    animation-timeline: scroll(root);
    animation-range: 0 100%;
    transform: none;
  }
}

@supports not (animation-timeline: scroll()) {
  .progress-bar {
    transform: scaleX(0);
    will-change: transform;
    transition: transform 0.1s linear;
  }
}

@keyframes scale {
  from {
    scale: 0 1;
  }
  to {
    scale: 1 1;
  }
}

body {
  font-size: 2.4rem;
  font-family: system-ui;
  margin: 0;
}
main {
  max-width: 600px;
  margin-inline: auto;
}
!

JS 

              
                // Vérification du support des scroll-driven animations
if (!CSS.supports("animation-timeline: scroll()")) {
  // Calcul de la progression du scroll
  function updateProgressBar() {
    const windowHeight = document.documentElement.scrollHeight - window.innerHeight;
    const progress = Math.min(window.scrollY / windowHeight, 1);
    progressBar.style.transform = `scaleX(${progress})`;
  }

  // Sélection de la barre de progression
  const progressBar = document.querySelector(".progress-bar");

  // Ajout des event listeners
  window.addEventListener("scroll", updateProgressBar, { passive: true });
  window.addEventListener("resize", updateProgressBar, { passive: true });

  // Initialisation
  updateProgressBar();
}
!
999px

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