If you notice that Shield is out of order, e.g. Security Admin...
... in all likelihood there’s another plugin installed on your site that’s being quite aggressive in enqueuing its own CSS styles all over the WP admin.
Best way to find it is disable each plugin (or theme), 1 at a time, and reload the Shield admin. When it loads normally, you’ve found the problem plugin.
Feel free to share that with us when you find it and we can take a look… best thing though is to reach out to the problem plugin and ask them to be much more selective about which WP admin pages they’re enqueuing their CSS styles, since they don’t need to force it on every admin page.