Placement

Four sides, each with an optional alignment: top, right, bottom, left, any of them suffixed -start, -center or -end, plus center for a card with no target at all.

You’re stating a preference here, not a coordinate. When the card doesn’t fit, the browser’s position-try-fallbacks flips it. On the JS path, your fallbackPlacements get tried in order and the card gets clamped into the viewport. The arrow is measured afterward, so it always agrees with where the card actually landed.

Each placement is demonstrated live at the live demo.