Current customization for hypothesis annotation layer. See post here: https://tomcritchlow.com/2019/02/12/annotations/

hypothesis-gist.js

<script type="application/json" class="js-hypothesis-config">
  {
    "openSidebar": false,
    "theme": "clean"
  }
</script>

<script src="https://hypothes.is/embed.js" async></script>

<script type="text/javascript">

window.hypothesisConfig = function () {
  return {
    branding: {
      appBackgroundColor: 'white',
      ctaBackgroundColor: 'rgba(3, 11, 16, 1)',
      ctaTextColor: '#eee',
      selectionFontFamily: 'helvetica, arial, sans serif'
    }
  };
};

</script>