grid-auto-flow: dense with minmax() – unresolved placement rule for multi‑track items

Unresolved Placement of grid‑auto‑flow: dense with minmax()

Goal: determine how browsers place items when grid-auto-flow: dense is used together with minmax() for auto‑generated tracks, especially after a spec upgrade that may alter the algorithm.

Constraints: items span multiple tracks, tracks defined by minmax(100px, auto), and the layout is rendered in Chrome, Firefox, Safari, and Edge.

Uncertainty: Chrome may shift items earlier to fill gaps, Firefox preserves document order, Safari shows deprecation warnings, and Edge falls back to implicit grid. The spec still evolves.

• What is the exact placement algorithm browsers use when grid-auto-flow: dense is combined with minmax() for auto‑generated rows and columns?
• How does a failed upgrade to a newer CSS spec (e.g., enabling subgrid via @supports) affect the dense placement behavior across browsers?
• What console or devtools messages indicate a deviation from the intended placement, and how can they guide a safe recovery?