- Update primary blue from Linear style (#3498db) to macOS system blue (#0A84FF)
- Align gray scale with macOS dark mode palette (#1C1C1E, #2C2C2E, etc.)
- Adjust dark mode background to match macOS systemBackground (HSL 240 5% 12%)
- Refine scrollbar colors to use native macOS gray tones
- Remove transparent titleBarStyle for better stability