As part of a gradual process to convert the UI to standard HTML and CSS, Firefox 113 deleted a group of proprietary CSS properties whose names start with -moz-box, including -moz-box-ordinal-number, which was often used in CSS rules as a hack to change the vertical sequence of elements. There are now standard CSS properties you need to use instead.
You can get links and code suggestions in the following Mozilla Support thread, or on the FirefoxCSS subreddit:
