Hi John,
Yes, our CSS code works.
Both Additional CSS and Theme Options > CSS are global CSS (sitewide application)
The difference is if you put exactly the same CSS on those areas, the one on Theme Options > CSS will be applied and the one on Additional CSS is overwritten. That is because of the Theme Options > CSS is called after the Additional CSS, overwriting all the CSS that is conflicting.
In short Theme Options > CSS has the priotity
However, if the custom CSS that is on Additional CSS has the higher CSS Specificity value, then that is a different story.
CSS Specificity: Things You Should Know
Thanks,