[Feature Request] Core support for dark mode

[tabacitu]

Feature Request

What's the feature you think Backpack should have?

In PRs like Laravel-Backpack/theme-tabler#101 we add some CSS for dark mode. But it's tied to that particular theme, since we use the colors of that theme.

We should have dark mode support in CRUD itself, in common.css. Then each theme that implements dark mode would have dark mode, out-of-the-box. If they need to customize some colors? Fine, they only override those with !important.

Have you already implemented a prototype solution, for your own project?

No I haven't yet. We can do this when we create theme-bootstrap. That theme is super basic, but it does have dark mode. And if that one can use the core dark mode, all themes can use core dark mode.

Do you see this as a core feature or an add-on?

Core feature. Should do. 6.x.