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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>

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.

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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.

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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 

              
                <main>
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent quis vulputate nulla, scelerisque rutrum urna. Curabitur mauris orci, sodales eu neque sit amet, venenatis finibus lorem. Vestibulum pulvinar odio eget eros luctus, at aliquam purus molestie. Donec elementum nunc et mi vestibulum egestas. Integer quis nunc condimentum, porta erat et, pulvinar purus.</p>
  <img src="https://www.ampproject.org/static/img/docs/pwamp_add_to_homescreen.png" width="848" height="1500">
  <p>Mauris et condimentum lacus. Praesent metus tellus, elementum sit amet nunc non, ultrices feugiat risus. Maecenas auctor elit vitae metus sagittis porta. Quisque finibus suscipit ultrices. Nulla turpis eros, convallis sit amet est sed, pulvinar malesuada dolor. Morbi bibendum mi non dui fringilla, quis porttitor ligula posuere. Aenean ultrices suscipit libero, sit amet feugiat velit molestie in.</p>
  <ul>
    <li>Look at me, I'm a list item</li>
    <li>Me too, guess what</li>
    <li>Hey, don't forget me! I know, I'm a really long entry but I deserve some love too. Can't you see that?</li>
    <li>OK if #3 can join, I want in as well</li>
    <li>Fine whatever, looks like we're all here now.</li>
  </ul>
  <p>Curabitur euismod leo libero, id scelerisque sapien maximus et. Praesent vehicula lacinia rutrum. Quisque vitae mauris dictum, finibus lectus sit amet, laoreet tortor. Nulla fermentum tortor arcu, ac aliquet diam vestibulum at. Ut tincidunt venenatis rhoncus. Morbi blandit consectetur tincidunt. Vestibulum sit amet velit vitae arcu accumsan luctus. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Morbi eu pellentesque ligula, at pharetra lectus. Fusce et augue porta, pellentesque felis vehicula, mollis neque. Aenean non purus a mauris lacinia iaculis vel in sapien. Aliquam ante metus, sodales quis fringilla in, rhoncus eu metus.</p>
  <p>Nulla ultrices, justo vestibulum blandit mollis, magna orci placerat nisl, a tincidunt dui diam a nisl. Nam a nulla pharetra, dapibus eros sed, egestas felis. Donec ac enim eget eros tempus dignissim ac vitae risus. Donec a mi a est fringilla congue et non leo. In hac habitasse platea dictumst. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Vestibulum nec consectetur nulla. Praesent venenatis elit vehicula tincidunt tincidunt. Morbi erat nunc, maximus at porttitor eget, gravida ut quam.</p>
  <p>Pellentesque in felis in est sodales mattis. Integer neque magna, gravida sit amet nisi id, dignissim imperdiet lectus. Donec ut nisi est. Suspendisse convallis tempus volutpat. Nunc venenatis hendrerit ligula, eget molestie magna pulvinar nec. Nam id luctus ex, eget finibus felis. Sed efficitur lacus vitae congue euismod. Vivamus lobortis purus eu sem tristique, vel sagittis dolor volutpat. Mauris dictum malesuada felis, sit amet dapibus mi. Pellentesque et finibus mauris. Phasellus metus ipsum, ullamcorper vitae neque sed, sollicitudin interdum odio. Sed ut urna efficitur urna fermentum faucibus et at ligula.</p>

</main>
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CSS 

              
                body {
  font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif;
}

main {
  width: 80%;
  max-width: 800px;
  margin: 0 auto;
  padding: 1em 2em;
  background: #f5f6f5;
  box-sizing: border-box;
}

img {
  width: 33%;
  height: auto;
  float: left;
}

ul {
  /* just for visualization purposes */
  border: 1px solid red;
  
  /* display: inline-block; */
  /* display: flex; /* 
  /* flex-direction: column; */
  /* overflow: hidden; */
}
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JS
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999px

Console