Enhancement: follow light/dark mode of PL

[phocks]

Odyssey light/dark theme has traditionally been a content producer-controlled option. With Presentation Layer introducing user-controlled light/dark mode switching, we should consider building that behaviour into Odyssey (possibly an optional setting that can be overridden).

Here's a proof of concept that seems to work:

https://github.com/abcnews/interactive-artemis-ii/blob/c0d3da7d4ef87752d57b1d04f080376235226650/src/lib/darkModeSwitcher.ts

Screen.Recording.2026-02-04.at.5.52.30.pm.mp4

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There may be additional classes and datasets that need to be changed and checked on elements other than these (maybe blocks or something), but this should be enough to get started.

const main = document.querySelector(".Main") as HTMLElement;
const header = document.querySelector(".Header") as HTMLElement;

header?.classList.remove("is-dark");
header.dataset.scheme = "light";
main.dataset.scheme = "light";

[drzax]

This looks like a really neat solution. Unfortunately, I don't think it'll be possible to default to this mode due to backward compatibility issues. At least not initially. We could at some point sunset the current Odyssey document in CM and lock it to a major version.