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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.

              <div class="intro">
  <p class="mw">This is a run of text in Merriweather.</p>
  <p class="gg">This is a run of text in Georgia.</p>
  <p class="gg-adj">This is a run of text in Georgia with font-size-adjust set to 0.555, which is the (estimated) aspect ratio for Merriweather.</p>

<div class="fallback">
  <p>This is a run of text that's supposed to be set in <em>Noticia Text</em> but the font doesn't exist, so the fallback of <em>Georgia</em> has been invoked, with the font-size-adjust set to 0.530, which is the estimated aspect ratio of Noticia Text. Georgia has an estimated aspect ratio of 0.481.
              @import url('https://fonts.googleapis.com/css?family=Merriweather');

body {
  padding: 1em;

@supports not (font-size-adjust: 0.5) {
  body::before {
    content: 'If you see this message, it means the demo is not working as the browser you are using does not support font-size-adjust.';
    display: block;
    background-color: coral;
    padding: 0.5em;
    margin-bottom: 1em;

div {
  padding: 1em;
  line-height: 1.5;

.intro {
  border: 0.25em dotted;
  p:not(:last-of-type) {
    margin-bottom: 1em;

.mw {
  font-family: Merriweather;

.gg {
  font-family: Georgia;

.gg-adj {
  font-family: Georgia;
  font-size-adjust: 0.555;

.fallback {
  font-family: 'Noticia Text', Georgia, serif;
  font-size-adjust: 0.530;
              /* Had a little chat with Robin Rendle earlier today about the `font-size-adjust` property and decided to make a demo to demonstrate it. MDN actually has a pretty good demo already at: https://developer.mozilla.org/en-US/docs/Web/CSS/font-size-adjust

So every font has an aspect ratio, which is the ratio of the height of the lower-case x against the height of the font in px. `font-size-adjust` lets us set the aspect ratio of the fall-back font to that of the first choice font.

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