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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.

              <!-- Try adding these classes to the DIV to toggle features on and off:  -->
<!-- screen-s  -->
<!-- screen-m  -->
<!-- screen-w  -->
<!-- no-wdth  -->
<!-- no-opsz  -->
<!-- with-GRAD -->
<div id="demo__container" class="container screen-l">

  <div id='demo-controls'>
    <div class="controls screen-width">
      <input type="radio" name="screen-width" value="screen-s" id="controls__small" class="controls--small"> <label for="controls__small">Narrow</label>
      <input type="radio" name="screen-width" value="screen-m" id="controls__medium" class="controls--medium"> <label for="controls__medium">Medium</label>
      <input type="radio" name="screen-width" value="screen-l" id="controls__large" class="controls--large" checked> <label for="controls__large">Wide</label>
    <div class="controls features">
      <input type="checkbox" name="feature" value="opsz" id="controls__opsz" class="controls--opsz opposite" checked> <label for="controls__opsz">Optical Size</label>
      <input type="checkbox" name="feature" value="wdth" id="controls__wdth" class="controls--wdth opposite" checked> <label for="controls__wdth">Width</label>
      <input type="checkbox" name="feature" value="GRAD" id="controls__GRAD" class="controls--GRAD"> <label for="controls__GRAD">Grade</label>

  <div class="paragraph">

    <h1>Metamorphosis in Type Design</h1>
    <p>Variable font design is a biological process by which a typeface physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the structure of the glyphs through cell growth and differentiation. Some historical
      styles can undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Glyphs that go through metamorphosis are called variable. Typefaces can be divided into styles that undergo complete metamorphosis, incomplete
      metamorphosis, or no metamorphosis.
              /* Amstelvar Variable Font */
@font-face {
  font-family: "Amstelvar VF";
  src: url("https://s3-us-west-2.amazonaws.com/s.cdpn.io/57225/AmstelvarAlpha-VF_v1.1.ttf")
  font-display: swap;

#demo__container {
  /* Breakpoint variables */
  --bp-small: 24.15;
  --bp-medium: 43.75;
  --bp-large: 60.25;
  --bp-xlarge: 75;

  --text-GRAD: 88;

  /* Paragraph variables */
  --p-line-height-min: 1.3;
  --p-line-height-mid: 1.4;
  --p-line-height-max: 1.5;
  --p-font-size-min: 1;
  --p-font-size-mid: 1.125;
  --p-font-size-max: 1.25;
  --p-vf-wght: 400;
  --p-vf-GRAD: 92;
  --p-vf-wdth-s: 80;
  --p-vf-wdth-m: 90;
  --p-vf-wdth-l: 100;
  --p-vf-opsz-s: 16;
  --p-vf-opsz-m: 18;
  --p-vf-opsz-l: 20;

  /* H1 variables */
  --h1-line-height-min: 1;
  --h1-line-height-mid: 1.125;
  --h1-line-height-max: 1.25;
  --h1-font-size-min: 2;
  --h1-font-size-mid: 2.2;
  --h1-font-size-max: 3.333;
  --h1-vf-wght-multiplier-s: 1.1;
  --h1-vf-wght-multiplier-m: 1.1;
  --h1-vf-wght-multiplier-l: 1.1;
  --h1-vf-opsz-s: 32;
  --h1-vf-opsz-m: 48;
  --h1-vf-opsz-l: 60;
  --h1-vf-wdth-s: 84;
  --h1-vf-wdth-m: 93;
  --h1-vf-wdth-l: 86;

  /* H2 variables */
  --h2-line-height-min: 1.5;
  --h2-line-height-mid: 1.5;
  --h2-line-height-max: 1.5;
  --h2-font-size-min: 1.125;
  --h2-font-size-mid: 1.375;
  --h2-font-size-max: 1.5;
  --h2-vf-wght-multiplier-s: 1.7;
  --h2-vf-wght-multiplier-m: 1.7;
  --h2-vf-wght-multiplier-l: 1.7;
  --h2-vf-opsz-s: 10;
  --h2-vf-opsz-m: 26;
  --h2-vf-opsz-l: 32;
  --h2-vf-wdth-s: 80;
  --h2-vf-wdth-m: 90;
  --h2-vf-wdth-l: 100;

  .paragraph {
    margin-left: auto;
    margin-right: auto;
    max-width: 95vw;
    width: 45em;
    &, * {
      transition: all 1s ease-in-out;
  &.screen-s .paragraph {
    width: 20em;
    max-width: 75vw;
  &.screen-m .paragraph {
    width: 30em;
    max-width: 85vw;

  .paragraph p {
    font-family: "Amstelvar VF", Georgia, "New Times Roman", serif;
    font-weight: normal;
    font-feature-settings: "liga" 1, "kern" 1;
    font-style: normal;
    margin-left: auto;
    margin-right: auto;
    -webkit-hyphens: auto;
    -moz-hyphens: auto;
    -ms-hyphens: auto;
    hyphens: auto;

  /* Variations for font size and line height */
  .paragraph p {
    font-size: calc(var(--p-font-size-min) * 1rem);
    font-variation-settings: "wght" var(--p-vf-wght), "wdth" var(--p-vf-wdth-s),
      "opsz" var(--p-vf-opsz-s), "GRAD" var(--text-GRAD);
    line-height: var(--p-line-height-min);

  &.screen-m .paragraph p {
    font-variation-settings: "wght" var(--p-vf-wght), "wdth" var(--p-vf-wdth-m),
      "opsz" var(--p-vf-opsz-m), "GRAD" var(--text-GRAD);
    line-height: var(--p-line-height-mid);
  &.screen-l .paragraph p {
    font-size: calc(var(--p-font-size-max) * 1em);
    font-variation-settings: "wght" var(--p-vf-wght), "wdth" var(--p-vf-wdth-l),
      "opsz" var(--p-vf-opsz-l), "GRAD" var(--text-GRAD);
    line-height: var(--p-line-height-max);

  .paragraph h1 {
    font-family: "Amstelvar VF", Georgia, "New Times Roman", serif;
    font-feature-settings: "liga" 1, "kern" 1;
    font-size: calc(var(--h1-font-size-min) * 1em);
    font-variation-settings: "wght"
        calc(var(--p-vf-wght) * var(--h1-vf-wght-multiplier-s)),
      "wdth" var(--h1-vf-wdth-s), "YTLC" 500, "YTAS" 680, "YTDE" 190, "YTUC" 720,
      "opsz" var(--h1-vf-opsz-s), "grad" var(--text-GRAD);
    line-height: var(--h1-line-height-min);
    margin: 0 auto 0 auto;
  &.screen-m .paragraph h1 {
    line-height: var(--h1-line-height-mid);
    font-size: calc(var(--h1-font-size-mid) * 1em);
    font-variation-settings: "wght"
        calc(var(--p-vf-wght) * var(--h1-vf-wght-multiplier-m)),
      "wdth" var(--h1-vf-wdth-m), "YTLC" 500, "YTAS" 715, "YTDE" 190, "YTUC" 735,
      "opsz" var(--h1-vf-opsz-m), "GRAD" var(--text-GRAD);
  &.screen-l .paragraph h1 {
    font-size: calc(var(--h1-font-size-max) * 1em);
    font-variation-settings: "wght"
        calc(var(--p-vf-wght) * var(--h1-vf-wght-multiplier-l)),
      "wdth" var(--h1-vf-wdth-l), "YTLC" 500, "YTAS" 750, "YTDE" 250, "YTUC" 750,
      "opsz" var(--h1-vf-opsz-l), "GRAD" var(--text-GRAD);
    line-height: var(--h1-line-height-max);

  .paragraph h2 {
    font-family: "Amstelvar VF", Georgia, "New Times Roman", serif;
    font-feature-settings: "liga" 1, "kern" 1;
    font-size: calc(var(--h2-font-size-min) * 1em);
    font-variation-settings: "wght"
        calc(var(--p-vf-wght) * var(--h2-vf-wght-multiplier-s)),
      "wdth" var(--h2-vf-wdth-s), "opsz" calc(var(--h2-font-size-min) * 16),
      "GRAD" var(--text-GRAD);
    line-height: var(--h2-line-height-min);
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 0;
    text-transform: uppercase;
  &.screen-m .paragraph h2 {
    line-height: var(--h2-line-height-mid);
    font-size: calc((var(--h2-font-size-mid) * 1em));
    font-variation-settings: "wght"
        calc(var(--p-vf-wght) * var(--h2-vf-wght-multiplier-m)),
      "wdth" var(--h2-vf-wdth-m), "opsz" calc(var(--h2-font-size-mid) * 16),
      "GRAD" var(--text-GRAD);
  &.screen-l .paragraph h2 {
    font-size: calc(var(--h2-font-size-max) * 1em);
    font-variation-settings: "wght"
        calc(var(--p-vf-wght) * var(--h2-vf-wght-multiplier-l)),
      "wdth" var(--h2-vf-wdth-l), "opsz" calc(var(--h2-font-size-max) * 16),
      "GRAD" var(--text-GRAD);
    line-height: var(--h2-line-height-max);

  &.no-opsz {
    --p-vf-opsz-s: 12;
    --p-vf-opsz-m: 12;
    --p-vf-opsz-l: 12;
    --h1-vf-opsz-s: 12;
    --h1-vf-opsz-m: 12;
    --h1-vf-opsz-l: 12;
    --h2-vf-opsz-s: 12;
    --h2-vf-opsz-m: 12;
    --h2-vf-opsz-l: 12;

  &.no-wdth {
    --p-vf-wdth-s: 100;
    --p-vf-wdth-m: 100;
    --p-vf-wdth-l: 100;
    --h1-vf-wdth-s: 80;
    --h1-vf-wdth-m: 80;
    --h1-vf-wdth-l: 80;
    --h2-vf-wdth-s: 100;
    --h2-vf-wdth-m: 100;
    --h2-vf-wdth-l: 100;

  &.with-GRAD {
    --text-GRAD: 125;

  /* Control buttons */
  .controls {
    margin-top: 2em;
    text-align: center;

    h3 {
      display: inline;
      font-weight: normal;
      font-family: monospace;

                var container = document.getElementById('demo__container');
  var controls = document.getElementById('demo-controls');
  controls.addEventListener('change', function(evt) {
    var input=evt.target;
    switch (input.name) {
      case "screen-width":
      case "feature":
        var opposite = input.classList.contains('opposite');

  if (opposite) {
    container.classList[input.checked ? 'remove' : 'add']('no-' + input.value);
  }         else {
    container.classList[input.checked ? "add" : "remove"]('with-' + input.value);


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