Custom CSS in Movable Type 5

As I covered in my last post, I have two subdomains: one for the CaSt blog and another for linked items (actually, there’s a third for archives).
Each subdomain has its own css file. For my purposes, all three use the same code and I was trying to manage updates on all three. It struck me what a waste of effort that is when I glanced at the beginning of the default styles.css document where the main css elements are imported into the file like so:
@import url(https://carryingstones.com/mt-static/themes-base/blog.css);
My latest discovery led me to pull all of my custom css into a single file—cast.css—and import it into the root styles.css in the respective directories.
Note that you can make those changes in your text editor of choice and upload them using your preferred file transfer methods; however, you have to save and publish each of the updated pages through the Movable Type dashboards. Find the appropriate files to republish under Design → Templates, then select the Stylesheet template (styles.css).
My apologies to anyone who may be rolling their eyes at this MT newbie. I’ll move on to other more entertaining items soon. I am writing about such basics because I had such a difficult time finding helpful tutorials, and hope to help others with articles like this one.