Editorial motion: restrained, fast, physical. Tier 1 lives in the kit primitives — every page gets it for free.
Backdrop fade + dialog scale-from-95%. 180ms.
Slide-in from right with layout reflow when stacked. 200ms.
Underline slides between tabs — never jumps. 240ms.
Color crossfades when status changes. Click to cycle.
Validation messages slide-down 4px + fade. 200ms.
Single slow sweep, not a tech-y pulse. Respects prefers-reduced-motion.
OS-level prefers-reduced-motion sets all transitions to ~0ms via globals.css. Verify by toggling your system setting.