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HTML

About HTML Preprocessors

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

The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.

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

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-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

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You can apply CSS to your Pen from any stylesheet on the web. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself.

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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.

Add External Scripts/Pens

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You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

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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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About Packages

Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.

All packages are different, so refer to their docs for how they work.

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HTML 

              
                <!-- first example -->
<div class="container">
  <form action="">
    <div class="form-row">
      <label for="name">Name:</label>
      <input type="text" id="name">
    </div>
    <div class="form-row">
      <label for="favColor">Favorite Color:</label>
      <input type="text" id="favColor">
    </div>
  </form>
</div>

<!-- second example -->
<div class="column-layout">
  <div class="main-column">
    <h2>Main Column</h2>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ipsam voluptatibus soluta, consequuntur, reiciendis debitis omnis fugiat libero pariatur amet laudantium minima consectetur tenetur. Repudiandae, autem, voluptate modi deleniti sequi voluptatum!</p>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Nisi earum fugit veniam amet quae sint vitae numquam dolore sunt quod a odio officia voluptate doloribus, at. Cum quasi mollitia eaque. Voluptatibus soluta, consequuntur, reiciendis debitis omnis fugiat libero pariatur amet laudantium.</p>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ipsam voluptatibus soluta, consequuntur, reiciendis debitis omnis fugiat libero pariatur amet laudantium minima consectetur tenetur. Repudiandae, autem, voluptate modi deleniti sequi voluptatum!</p>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Nisi earum fugit veniam amet quae sint vitae numquam dolore sunt quod a odio officia voluptate doloribus, at. Cum quasi mollitia eaque.</p>
  </div>

  <div class="sidebar-one">
    <h3>Sidebar One</h3>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Voluptatum modi nisi tenetur sint dignissimos nulla, blanditiis nesciunt.</p>
  </div>

  <div class="sidebar-two">
    <h3>Sidebar Two</h3>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Voluptatum modi nisi tenetur sint dignissimos nulla, blanditiis nesciunt.</p>
  </div>
</div>

<!-- third example -->
<div class="call-outs-container">
  <div class="call-out">
    <h4>Feature 1</h4>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quibusdam obcaecati vel, placeat numquam omnis sit consectetur nobis molestias! Explicabo deserunt. Consectetur adipisicing elit. Quibusdam obcaecati vel, placeat numquam placeat numquam omnis sit consectetur.</p>
  </div>

  <div class="call-out">
    <h4>Feature 2</h4>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quibusdam obcaecati vel, placeat numquam omnis sit consectetur nobis molestias! Explicabo deserunt placeat numquam omnis.</p>
  </div>

  <div class="call-out">
    <h4>Feature 3</h4>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quibusdam obcaecati vel, placeat numquam omnis sit.</p>
  </div>
</div>

<!-- fourth example -->
<div class="fixed-size-container">
  <div class="fixed-size">1</div>
  <div class="fixed-size">2</div>
  <div class="fixed-size">3</div>
  <div class="fixed-size">4</div>
  <div class="fixed-size">5</div>
</div>

<!-- fifth example -->
<div class="banner">
  <div class="center-me">Center Me Plz</div>
</div>

<!-- sixth example -->
<div class="equal-height-container">
  <div class="first">
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ipsam quasi similique amet voluptatem molestiae nostrum ab nesciunt blanditiis repellendus quos, sequi sunt, dolorem quis facilis mollitia nemo modi doloribus quo.</p>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Placeat quisquam, veritatis ducimus, vero magnam hic quia pariatur asperiores laudantium quod nobis perspiciatis, expedita quo reprehenderit quasi iusto ullam error reiciendis.</p>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ipsam quasi similique amet voluptatem molestiae nostrum ab nesciunt blanditiis repellendus quos, sequi sunt, dolorem quis facilis mollitia nemo modi doloribus quo.</p>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Placeat quisquam, veritatis ducimus, vero magnam hic quia pariatur asperiores laudantium quod nobis perspiciatis, expedita quo reprehenderit quasi iusto ullam error reiciendis.</p>
  </div>

  <div class="second">
    <div class="second-a">A</div>
    <div class="second-b">B</div>
  </div>
</div>
!

CSS 

              
                html, body {
  padding: 0;
  margin: 0;
}

input {
  font-size: 14px;
  font-family: Helvetica, sans-serif;
}

body {
  background-color: #BBB;
  font-family: Helvetica, sans-serif;
  padding-bottom: 100px;
}

h2, h3 {
  margin: 0 0 .75em 0;
}

/* first example */
.container {
  max-width: 750px;
  margin: 20px auto 0 auto;
  padding: 30px;
  background-color: #FFF;
}

.form-row {
  padding: 10px 0;
  display: flex;
}

.form-row label {
  padding-right: 10px;
}

.form-row input {
  flex: 1;
}

/* second example */
.column-layout {
  max-width: 1300px;
  background-color: #FFF;
  margin: 40px auto 0 auto;
  line-height: 1.65;
  padding: 20px 50px;
  display: flex;
}

.main-column {
  flex: 3;
  order: 2;
}

.sidebar-one {
  flex: 1;
  order: 1;
}

.sidebar-two {
  flex: 1;
  order: 3;
}

/* third example */
.call-outs-container {
  max-width: 1400px;
  margin: 40px auto 0 auto;
}

.call-out {
  padding: 20px;
  box-sizing: border-box;
  margin-bottom: 20px;
  flex-basis: 30%;
}

@media (min-width: 900px) {
  .call-outs-container {
    display: flex;
    justify-content: space-between;
  }
}

.call-out:nth-child(1) {background-color: #c0dbe2;}
.call-out:nth-child(2) {background-color: #cdf1c3;}
.call-out:nth-child(3) {background-color: #ccb9da;}

/* fourth example */
.fixed-size-container {
  max-width: 1400px;
  margin: 40px auto 0 auto;
  background-color: #FFF;
  padding: 30px 0;
  display: flex;
  align-items: center;
  justify-content: space-around;
  flex-wrap: wrap;
}

.fixed-size {
  width: 150px;
  height: 100px;
  background-color: #990b47;
  color: #FFF;
  line-height: 100px;
  text-align: center;
  font-weight: bold;
  font-size: 60px;
  margin-bottom: 20px;
}

/* fifth example */
.banner {
  height: 400px;
  max-width: 700px;
  margin: 40px auto 40px auto;
  background-color: #2a2a2a;
  display: flex;
}

.center-me {
  color: #FFF;
  font-size: 50px;
  margin: auto;
}

/* sixth example */
.equal-height-container {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
}

.first {
  background-color: #FFF;
  padding: 20px;
  flex: 1;
}

.second {
  background-color: yellow;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.second-a {
  background-color: #c0dbe2;
  flex: 1;
}

.second-b {
  background-color: #cdf1c3;
  flex: 1;
}
!

JS
!
999px

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