Theater mode with embedded video?

Hi, I’m wondering if it’s possible to switch an embedded video to a theater mode so that it fills the width of the browser that contains it. This is a nice feature in YouTube videos that enables the user to resize the video by resizing the browser, but without going into full screen mode. Using full-screen mode makes it difficult to take notes side-by-side in another application while viewing the video, which is important for a lot of users, including individuals with disabilities who write using voice recognition software. Thanks!