Scroll-out (exit) effect classes (.sf-exit--*)

[jackgranatowski]

Problem

We ship scroll-driven entrance effects (.sf-entrance--*) but no symmetric exit effects that trigger as an element scrolls out of view. The keyframes already exist (sf-fade-out, sf-scale-down) and --sf-transition-exit is defined.

Scope

• .sf-exit--fade / -fade-up / -fade-down / -scale-down etc., using animation-timeline: view() with a cover exit range.
• Graceful fallback where view() unsupported; prefers-reduced-motion safe.

Acceptance

• .sf-exit--* fire on scroll-out without JS
• Reduced-motion safe + documented

[jackgranatowski]

Shipped (active) in core/motion.css via #546.

---

Generated by Claude Code