Thank you, Emmanuele.
At this point I am still deciding the destiny of my widget. It is an emblem picker for my Nautilus Annotations extension (I had shared a preview in this post). It began as a simple specific widget, but it ended up being a very complete one, which allows to set the emblems of multiple files at the same time and manage possible inconsistencies between files without losses.
So I will probably first publish it with the next release of my extension. If it works well I might propose it to Nautilus developers (Nautilus still doesn’t have a way to set emblems as far as I know!). Or I might decide to release it as part of a separate module.
But In the meanwhile I need a CSS. So I will go with the static variable for now…
We are in the realm of subjectivity here. But in my mind “minimal” is that value below which you get zero. And that is what happens without setting a minimal :indeterminate selector for my widget: zero differentiation (basically a functionality gets lost).
―madmurphy