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HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

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

    <h1>Viewport Breakpoint Font Sizer</h1>

    <p><a href="" 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>


              // 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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