I am working on a website and recently installed Firefox to test it in other browsers. While testing on Mozilla, I noticed that the page does not fill the entire window; the html element ends where the purple background begins, and the vertical scroll bar should not be visible because there is nothing to scroll. The page works just fine on other browsers and devices. (You can test it on tyriadle.com > skills > select any option.) I tested it on other computers, and the result is the same on Mozilla.