The Dashboard theme in Azure can be changed. I didn't know this was possible until I came across a tweet by @msdev. I figured I'd pass this along and try to help spread the word for those who like to customize their experiences.
And for everyone who's curious, yes, there's a dark mode.
There are only a handful of themes currently, but the options also include high-contrast themes for those who need them. I've chosen to embed the video posted by Microsoft below.