How and what CSS can be added in Views UI?

@bunthorne
The styles can added by creating libraries. You may follow the URL https://www.drupal.org/docs/develop/creating-modules/adding-assets-css-js-to-a-drupal-module-via-librariesyml →

Also Make sure that you are using correct version of module according bootstrap theme version. But this is also not solving UI style issue due to Bootstrap framework is not apply on view result. So you may modify views template.

I see. Currently the code is using the base style where "row" actually means each "record" that is returned. I'll update to not use the base class but define a custom class.

If you update to the latest version of 5.5.0, you will find options for adding custom classes. You can add Bootstrap classes or your own. There is also help text with a link to more documentation in each settings panel.

Thanks, that helps somewhat. The only thing I would suggest would be to provide a sample in the documentation that parallels the documentation at Bootstrap. It could either go in the screenshot (instead of custom-card-class another-custom-card-class) or in the help text.

For example, the Boostrap example under Card#Text alignment showed

<div class="card text-center mb-3" style="width: 18rem;">

I was able to guess that I did not need the card part of the class; I put text-center in the Custom Card Class for the View to center all card elements.