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HTML

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CSS

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CSS Base

About CSS Base

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JavaScript

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JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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HTML 

              
                This text is set in [JAF Bernina Sans](https://typekit.com/fonts/jaf-bernina-sans), backed up by a Verdana stack. It uses a Sass map to scope font-size and line-height measurements to those specific typefaces, [as Robin Rendle described](http://erskinedesign.com/blog/setting-typographic-scale-with-sass-maps/). (Em units and max-widths, too.) See the variables and mixins in <a href="https://codepen.io/timbrown/pen/xrwvJ" target="_blank">this other Pen</a>.

Look at this Pen's own CSS and you'll see what I really wanted to explore. The paragraph element uses Verdana (and its associated measurements) by default, and only uses Bernina (and *its* associated measurements) if Bernina has loaded properly. The wf-active class is via [Typekit font events](https://help.typekit.com/customer/portal/articles/6787-font-events). Progressive enhancement FTW.

When the composition widens and reaches a breakpoint, its size gets bumped up — again, considering Verdana by default and Bernina *only if Bernina is present*.

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Tim Brown • [@nicewebtype](https://twitter.com/nicewebtype)
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CSS 

              
                p {
  @include font-scale(base);
  .wf-active & {
    @include font-scale(base, $font-bernina);
  }
  @include responsive(narrow-screens) {
    @include font-scale(text);
    .wf-active & {
      @include font-scale(text, $font-bernina);
    }
  }
}

body {
  margin: 2em;
  font-family: fontset-family($font-verdana);
  color: #444;
  @include responsive(narrow-screens) {
    margin: 2em 4em;
  }
}
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JS
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999px

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