Steps carry no content: the text belongs to the component that owns the target, with its props and providers. A step is a point, so it can be shared between guides.
Two lifecycle levels: the guide knows the route and the tab to open; the component knows its own state. Neither can do the other's job, so both get hooks, in a fixed order.
content, render and portal rather than one option: a component is the safe default, a function sees the closure, a portal inherits providers. Each has a cost the other two avoid.
Headless frame, shadcn chrome in the registry: positioning and aria are mechanics, the card and the buttons are yours. Changing a label is editing a file, not waiting for a prop.
Slow and fast state: runs and records change a few times per tour; target rects change on every scroll. They are two channels, so a scroll only re-renders the frame and the veil.
Routes are data: onPage is declarative and idempotent, which is what makes going backward across pages work without extra code.
No animation library: the frame animates in CSS from data-side, the veil transitions its clip-path.