Can someone tell me what goes in the "Additional CSS classes" field in the Style Settings section of the Configure block window?
Is it
#1. CSS code defining the class
or
#2. only the name of the class which I should define in a CSS file associated with the new theme (just a duplicate of the Basis theme) I'm using.
And if the answer is #2, in which of the default css files that come with the theme should I define the class?
Thanks.
Maybe a little off-topic, but there's a utility module (Utility CSS) that seems to provide autocompletion for that layout form field, based on the active theme.
I didn't use it yet, but it seems to be a good solution for less technical users, so they don't have to remember the css class names.