https://www.will-myers.com/scrolling-logo-in-squarespace
<script> (function(){ window.setInterval(function(){ var event = document.createEvent("Event"); event.initEvent("click", false, true); document.querySelectorAll(".gallery-reel-control .gallery-reel-control-btn")[1].dispatchEvent(event); }, 2000); })(); </script>
CSS in the main site CSS file too - scoped to the section-id of above
<script> alert("runs"); </script>