You're a data analyst. Below is a company's monthly revenue and headcount over 24 months. Build an interactive data visualization (one self-contained HTML file): a clean line/area chart of revenue over time with hover tooltips, a toggle to overlay headcount on a second axis, and a highlight marking the best and worst months. Vanilla JS + inline SVG or <canvas> — no charting libraries.
Data (CSV):
month,revenue,headcount
2024-05,82000,9
2024-06,88000,9
2024-07,91000,10
2024-08,86000,10
2024-09,103000,11
2024-10,118000,12
2024-11,121000,12
2024-12,99000,12
2025-01,134000,14
2025-02,142000,15
2025-03,151000,15
2025-04,148000,16
2025-05,167000,17
2025-06,182000,18
2025-07,179000,19
2025-08,195000,20
2025-09,214000,21
2025-10,238000,22
2025-11,251000,23
2025-12,229000,23
2026-01,272000,25
2026-02,288000,26
2026-03,301000,27
2026-04,319000,28
Make it genuinely interactive and polished — smooth, readable, with thoughtful axes and labels. Return only the HTML.
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