If you set Body Content Max Width property in Theme Roller of UT theme to some fixed value (other than Auto) your body content will be centered on the screen.
What if you want to reset this on specific pages and use the full width of the screen?
In this case, you should add the following line of the CSS to the page property Inline CSS:
If you want to define it in the static CSS file you can also reference it as:
...or the declarative way - just set region position to Before Content Body and set the margins. 🙂
Tested in APEX 21.1.5