Approximate reference curves. The centile bands are derived from typical UK growth patterns, not the exact licensed UK-WHO/UK90 tables — good enough to eyeball a trend or flag possible stimulant-related growth suppression, not for a precise centile/SDS figure. Any genuine concern should still go to paediatrics as usual. (For exact centiles, this widget can optionally call the RCPCH Digital Growth Charts API — see fetchCentileFromAPI() in the source — but that's not required for this use.)