@viwilson ...
If you take a look at the two links that I provided, you'll see that the Idea and Theme have been labeled as "Identified". A further explanation of this label can be found at:
How do Ideas and Themes work in the Instructure Co... - Instructure Community (canvaslms.com)
Look under the heading, "What are the Theme Stages?".
Also, as noted in the first link I provided, although there hasn't been an implementation as of yet for desktop/laptop users, dark mode is available in the Canvas Student, Canvas Teacher, and Canvas Parent apps you can download to your phone/tablet.
I know this might not be the response you're looking for...but I hope it helps to clarify things for you at this time.