One transition device per cut

A cut is only invisible when the last frame of one scene and the first frame of the next agree about every pixel that matters. deslgn's transition language builds that agreement as plain keyframes: a card grows until it IS the next scene's container; a glowing curtain covers the frame and drains away on the other side.

The rule the system enforces on itself: one device per cut. Never a wash stacked on a morph — that's how ghosts appear.