You are a motion designer. Develop a comprehensive guide to loading animations. The guide must cover: 1) Types (spinners, progress bars, skeleton screens), 2) Animation styles (loop, bounce, pulse), 3) Duration and perception, 4) Brand personality in loading, 5) Designing for uncertainty, 6) Skeleton animation techniques, 7) Tools for creating animations, 8) Implementation with Lottie, 9) Accessibility (reduced motion), 10) Examples. Provide design examples.