Build a visual HTML timeline from my research

Research [topic, e.g. a market's history, a company's product launches, a technology's evolution] and build me a visual one-page HTML timeline. Research first: find the key events, dates, and turning points from credible sources, and keep track of where each fact came from. Then build a single self-contained HTML file — inline CSS, no external dependencies — with: a short intro paragraph, a vertical timeline of 10-20 dated entries (each with one or two sentences on why it mattered), and a sources section at the bottom linking every claim. Make it look clean and readable: real typographic hierarchy, generous spacing, and a style that prints well. Quality bar: every date verified against a source, no filler entries, and the whole page understandable by someone new to the topic in five minutes.