Spatial Card Tunnel

Purpose

Use for a finite sequence of related cards that advances through restrained z-depth with explicit navigation.

Use when

• Three to ten documents, product surfaces or steps have a meaningful order.
• A tunnel communicates progression better than a flat list.

Avoid when

• The content is a comparison grid or a long feed.
• Users would need a camera gesture to reach information.

Interaction and accessibility

Keep all cards in DOM order, use a roving active item and expose Arrow/Home/End plus Previous/Next. Metadata must not depend on opacity or depth.

Reduced motion and performance

Flatten to a normal stack immediately. The collection is bounded and transform-only; avoid cloned cards, camera loops and WebGL.