Thanks for the thoughtful comment! Glad the scroll-timeline approach came through clearly, especially the point about keeping presentation and behavior separate.That was one of the main things I wanted to highlight with this pattern.
On browser support: I actually do cover this in the "Browser Support" section of the article, since you're right that animation-timeline: scroll() is still pretty new (currently solid in Chromium-based browsers, but not yet supported in Firefox or Safari). I probably should've surfaced it a bit more prominently rather than leaving it further down the page — appreciate you flagging that, it's a fair callout.
For a production fallback, the simplest approach is a @supports check: if animation-timeline isn't supported, you can fall back to a static scene (or swap in a JS-based scroll listener using IntersectionObserver or plain scroll events for browsers that need it). I might add a short code snippet for that to make it more actionable.
And yes — the reason I picked day-to-night specifically was to show how one timeline can drive several unrelated properties in sync without needing separate keyframe triggers for each. Really glad that landed the way I intended.
A scroll-driven animation is a great example of how modern CSS can create interactive effects without relying on JavaScript. Using scroll-linked animations keeps the implementation cleaner while separating presentation from behavior, making the code easier to maintain.
One suggestion would be to mention browser compatibility, since CSS scroll-driven animation features are still relatively new and may not behave consistently across all browsers. Including a graceful fallback or briefly explaining what users can expect in unsupported browsers would make the example even more practical.
I also like the day-to-night concept because it shows how multiple properties, such as background colors, element positions, and opacity, can stay synchronized with a single scroll timeline. It is a clear and engaging way to demonstrate the capabilities of modern CSS.