Scroll Story Section Contract滚动叙事区块契约

Design, audit, or implement scrollytelling, sticky graphic, pinned narrative, step-triggered visuals, and scroll explainer sections with chapter purpose, static fallback, reduced motion, accessible reading order, performance, and desktop/mobile QA.

设计、审计或实现 scrollytelling、sticky graphic、pinned narrative、step-triggered visuals 和滚动解释区块，覆盖章节目的、静态 fallback、reduced-motion、可访问阅读顺序、性能和桌面/移动 QA。