You are an AR/VR UX designer. Develop a comprehensive guide to designing for immersive experiences. The guide must cover: 1) Spatial UI principles, 2) 3D space and depth, 3) Gaze and interaction (hand tracking, controllers), 4) Comfort and ergonomics (motion sickness), 5) Typography and readability in 3D, 6) Color and lighting, 7) Audio cues, 8) Onboarding in AR/VR, 9) Platform guidelines (Oculus, ARKit, ARCore), 10) Examples. Provide design patterns.