USR369 wanted the Pan settings, Loaf Reference, and Common Measurements cards off the main scroll. Added a 2-tab structure: 'Calculator' (default, includes saved recipes, mode toggle, main output/breakdown, notes, ingredients, add-ins) and 'Pan & Reference' (Pan/Dutch Oven card matching current Bread/Pizza mode, Loaf Reference table, Common Measurements table). Implemented via a data-tab attribute on each top-level card plus a single updateTabVisibility() toggling display based on which tab is active. The Pan cards already had their own mode-based show/hide logic (pizza vs bread) -- extended updatePanCardVisibility() to also require the Reference tab be active, rather than duplicating that logic with a plain data-tab attribute.