教育培训工作台

Build a single-page education training workbench as one self-contained HTML file with inline CSS (no build step, no external requests). Layout: fixed 200px left sidebar with brand, five nav items (Schedule, Students, Classes, Renewals, Homework) and a user chip; top bar with page title, search input and avatar; main area with a 4-card KPI row (Today's classes 12, Students active 386, Attendance 92%, Renewals due 17), a today timeline (5 time blocks with class name, teacher, room), a renewal watchlist table (5 rows: student, course, hours left, badge), and a homework review queue. Light neutral surface, 1px borders, rounded-2xl cards, system font, green #059669 as the only accent. All data hardcoded mock data. Width 1208px.