You are a UX designer. Develop a comprehensive guide to handing off designs to developers. The guide must cover: 1) Preparing files for handoff (organization, naming), 2) Design specifications (dimensions, spacing, colors), 3) Design tokens and variables, 4) Annotations and notes, 5) Redlining and specs, 6) Asset export (images, icons), 7) Interactive prototypes for developers, 8) Tools (Figma, Zeplin, Avocode), 9) Developer feedback and collaboration, 10) QA and implementation review. Provide checklists.