amp-dynamic-css-classes

<script async custom-element="amp-dynamic-css-classes" src="https://cdn.ampproject.org/v0/amp-dynamic-css-classes-0.1.js"></script>

<style amp-custom>
  :root {
    --space-2: 1rem;   /* 16px */
  }
  body:not(.amp-referrer-pinterest-com) .if-pinterest,
  body:not(.amp-referrer-ampbyexample-com) .if-ampbyexample,
  body:not(.amp-referrer-google-com) .if-google,
  body:not(.amp-referrer-twitter-com) .if-twitter,
  body:not(.amp-referrer-linkedin-com) .if-linkedin,
  body:not(.amp-referrer-localhost) .if-localhost {
    display: none;
  }
  body:not(.amp-viewer) .if-viewer,
  body.amp-viewer .if-not-viewer {
    display: none;
  }
  .dynamic-css {
    padding: var(--space-2);
  }
</style>

<div class="if-pinterest dynamic-css">You were referred here or embedded by Pinterest!</div>
<div class="if-twitter dynamic-css">You were referred here or embedded by Twitter!</div>
<div class="if-google dynamic-css">You were referred here or embedded by Google!</div>
<div class="if-ampbyexample dynamic-css">You came here directly!  Cool :)</div>
<div class="if-localhost dynamic-css">You came here directly!  Cool :)</div>

<div class="if-not-viewer dynamic-css">Hey! You're not visiting within the context of an AMP Viewer!</div>
<div class="if-viewer dynamic-css">Ahoy! Since you're coming from a viewer.</div>