bugfix: giscus light dark toggle on load

[gordonwoodhull]

Simpler alternative to #12608

Wait for giscus to load and then set its light/dark toggle immediately.

This is failing on Safari. May still need a Mutation Observer for the iframe.

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[gordonwoodhull]

Okay, it works with a MutationObserver waiting for giscus to load.

Although this is a long chain of callbacks, and we did not manage to avoid MutationObserver, IMO this is simpler and more straightforward than dynamically loading the giscus script.

I wish I could keep going and remove the author preference from the giscus parameters, since it makes things more complicated to have the base and alternate themes swapped, and I don't see what it helps.

But think it’s easier and safer to expose const authorPrefersDark and fix the "reversed giscus" bug directly (first commit).

[feinmann]

I just found this, because in my quarto blog, deployed as gh-pages, giscus is not loading and I see in my javascript console the following:

Uncaught ReferenceError: authorPrefersDark is not defined

Any idea?

[gordonwoodhull]

Thanks @feinmann, I am able to reproduce with a site with Giscus but no dark mode.

I'll look into a fix for this.

[gordonwoodhull]

@feinmann, this is fixed in 1.7.31

[feinmann]

Thank you for the great work! It is already deployed :)