## Implementation Complete Created SVG-based 42U rack diagram component at frontend/src/components/rack-diagram.tsx. ### Features Implemented: - **42U rack display**: Vertical rack with numbered U positions (1-42, bottom to top per industry standard) - **Rack rails**: Visual mounting rails with hole patterns - **Unit markers**: U numbers on both left and right sides - **Theme support**: Uses Tailwind CSS variables for automatic dark/light theme support - **Slot highlighting**: - Empty slots: Dashed border with Available text - Occupied slots: Solid fill with device name and U height badge - Status indicators: Green (on), Red (off), Yellow (partial) - **Interactive**: Click handler support with onSlotClick prop - **Selection state**: Visual highlight for selected slot via selectedSlotU prop - **Accessibility**: ARIA labels for screen readers ### Files Added: - frontend/src/components/rack-diagram.tsx - Main component - frontend/src/components/rack-diagram.test.tsx - Test suite (11 tests) ### Test Results: All 11 new tests pass, all 41 total project tests pass.