YouTube Video Link in Post

Hi – thanks again for a great theme! In a previous support query you’ve said that you can just past the YouTube URL into a post, which I’ve done. However, the video is the full width of the page and not contained in the same style as the site.

Can you advise the best way to resize the YouTube player so that it’s the same width as the rest of the post content?

Thanks!

The page I need help with: [log in to see the link]