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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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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).

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient. For instance, CoffeeScript can help prevent easy-to-make mistakes and offer a cleaner syntax and Babel can bring ECMAScript 6 features to browsers that only support ECMAScript 5.

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Babel is required to process package imports. If you need a different preprocessor remove all packages first.

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About External Resources

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.

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HTML 

              
                <div class="container">
  <div class="inner">

    <h1>Viewport Breakpoint Font Sizer</h1>

    <p><a href="https://github.com/bixgomez/viewport-breakpoint-font-sizer" target="_blank">Available on GitHub!</a></p>

    <p>This is a Sass function I wrote to facilitate predictable viewport-based font sizes.</p>

    <p>I wrote it to accompany my conference session on viewport units.</p>

    <p>It uses simple math to deliver the combination of settings that will give us the font size we desire at a specific "threshold" breakpoint above which (and below which) we want the font size to increase at specific (and different) rates.</p>
    
    <p>That's a bit of a mouthful, but resize your browser (horizontally) and you'll see what I am on about!</p>

  </div>
</div>
!

CSS 

              
                // The maximum size you would like your site container to be.
// Can use any unit, including percents (so you can use 100% if you like).
$max-site-width: 1400px;

// The size you want your font to be at the "switch point".
$threshold-px: 14px;

// The breakpoint at which you want your font size to be $threshold-px.
$switch-point: 850px;

// The rate that you want font size to increase as browser width increases from $switch-point.
$vw-rate-up: 1.5vw;

// The rate that you want font size to increase as browser width decreases from $switch-point.
$vw-rate-down: 1.125vw;

$up-size: viewportFontSizer($threshold-px, $switch-point, $vw-rate-up, 'add');
$down-size: viewportFontSizer($threshold-px, $switch-point, $vw-rate-down, 'subtract');

.container {
  font-size: calc( #{$down-size} - #{$vw-rate-down} );
  max-width: $max-site-width;
  margin: 0 auto;
  background-color: rgba(white, .5);

  @media only screen and (min-width: $switch-point) {
    font-size: calc( #{$up-size} + #{$vw-rate-up} );
  }

  @media only screen and (min-width: $max-site-width) {
    font-size: calc( #{$up-size} + #{$max-site-width/100 * strip-unit($vw-rate-up)} );
  }
}



// Just the optional styling to make it pretty.
* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
}

body {
  background-color: rgba(black, .4);
  color: rgba(black, .75);
  font-family: helvetica, arial, sans-serif;
  font-size: 1em;
  margin: 0;
  padding: 1em;
}

h1, h2, h3, h4, p {
  margin-top: 0;
}

h1, h2, h3, h4 {
  margin-bottom: .5em;
}

p {
  margin-bottom: 1em;
  &:last-child {
    margin-bottom: 0;
  }
}

.container {
  max-width: $max-site-width;
  margin: 0 auto;
  background-color: rgba(white, .75);
}

.inner {
  padding: 1em;
}
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JS
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999px

Console