I saw a New York Times page on the web with a full-page video. You can see it yourself at https://www.nytimes.com/interactive/2019/09/23/opinion/data-privacy-jaron-lanier.html . It makes quite an impact.
I imagine this is easily doable in Sparkle, but when I tried, using a small cellphone-taken mp4 video as a test, I could not get it to work. I loaded the video on a fresh page, but I could not click “Full page width” on the Arrange tab because the option was greyed out.
I am quite the beginner when it comes to Sparkle. Does my problem have something to do with the dimensionality of my test video? Why is the “Full page width” option greyed out and how do I “ungrey” it?