smcodemeister/chronos-timeline ? reverse-engineered prompt

Build me a mobile friendly historical timeline page in a single HTML file.

I want it to feel clean and easy to scroll on a phone, with events shown in chronological order, short descriptions, dates, and a nice visual flow that makes the history easy to follow. Make it responsive, touch friendly, and readable without needing to zoom in. If it makes sense, add simple interactions like tapping an event to expand more details, or a way to jump between eras.

Keep the design polished and modern, but not flashy. Use clear typography, good spacing, and a layout that works well on small screens first. If you need to look up current best practices or browser support details, go ahead and check online. Please make the whole thing self contained and ready to open in a browser.