Youtube element has vertical scrollbars in firefox

I’m using the Youtube element inside a div set to max W:1100px and centred inside a full-width section. The video looks fine in Chrome but has a vertical scroll bar on the right-hand side in Firefox. Here is a screenshot: https://i.imgur.com/vYw6VpE.png Any thoughts on why this is happening?

Cheers
David


Here is my site Read-Only: [LINK]1
(how to share your site Read-Only link)

Anyone else seen this or know how to fix it?