Make Bootswatch paired light and dark themes available

[allefeld]

Description

For many of the Bootswatch themes there seem to be paired light and dark versions. For example, on the Cosmo theme page https://bootswatch.com/cosmo/ there is a switch in the upper right corner which toggles between the standard light version and a version which retains fonts, formatting, and many colors, but has light-on-dark text.

I tried to implement that for my own website using

    theme:
      light: cosmo
      dark: cosmo

and

    theme:
      light: cosmo
      dark: cosmo-dark

or

    theme:
      light: cosmo
      dark: cosmo_dark

but none of these work.

I downloaded the source code from the light and the dark version of the Cosmo theme page and compared the files, and the only difference seems to be that the html element has an additional attribute data-bs-theme="dark". Manipulating that manually via the inspector works on the Bootswatch theme page, but it does not work on Quarto-generated pages.

It would be nice if there was a way to take advantage of these paired themes in Quarto, instead of pairing two different light and dark themes.

[cderv]

I think this is quite a new feature as it was released in Bootstrap 5.3.0: https://blog.getbootstrap.com/2023/05/30/bootstrap-5-3-0/#dark-mode
So we don't leverage and support it yet.

I believe we are using 5.2.2 right now and we update such dependencies once per version. We already update for 1.4 (we do it at the start of a new version). So we probably we'll move to 5.3.0 for Quarto 1.5

This is indeed a good feature request to be able to leverage this feature ! probably quite some change though in our system.

cc @dragonstyle : should we create a specific issue to track this ?

[dragonstyle]

Great idea - created #6741

[cderv]

Great!

@allefeld I'll close this discussion and we should now track the issue. Thanks a lot for the suggestion !!

[allefeld]

Thanks!

[allefeld]

Checking back in with this, because 1.5 was started with the pre-release 1.5.0 in January, so I'm wondering whether the switch to Bootstrap 5.3.0 was made? I assume not, because the issue #6741 is open.

[cderv]

I think we did update to 5.3.1 but #6741 is still to be done. We marked it for 1.5 so hopefully we'll be able to find the time-resource to adapt Quarto theming system for this new feature.