Hi,
If this option is available for you (please check the quickstart guide) you can do this on the Advanced tab in the administration where styles can be changed.
Same domain:
https://www.tinywebgallery.com/blog/advanced-iframe/demo-advanced-iframe-2-0
e.g. -> iframe_content_id=”#iframe-content” iframe_content_styles =”color:#ff0000″
Subdomain:
https://www.tinywebgallery.com/blog/advanced-iframe/advanced-iframe-pro-demo/sub-domain-auto-height-and-css-modifications
e.g. -> iframe_content_id=”#iframe-content” iframe_content_styles =”color:#ff0000″
remote domain:
https://www.tinywebgallery.com/blog/advanced-iframe/advanced-iframe-pro-demo/external-workaround-auto-height-and-css-modifications
e.g.
<script>
var iframe_content_id = “#iframe-content”;
var iframe_content_styles = “color:#ff0000”;
</script>
<script src=”<your domain>/wp-content/plugins/advanced-iframe/js/ai_external.js”></script>
