Visual proof: a² + b² = c²

An education explainer that proves the Pythagorean theorem visually with the classic rearrangement proof. Light chalk-paper look (#fbfaf6 background, dark ink #1d1d1f, teal #0f8b8d and amber #e8a33d accents), drawn with inline SVG. Beats: (1) title 'Why a² + b² = c²' and a right triangle with sides labelled a, b, c; (2) squares grow on each side, coloured and labelled a², b², c²; (3) a big square of side a+b containing four copies of the triangle arranged around a tilted square of area c²; (4) the four triangles slide to a new arrangement inside the same big square, leaving two squares a² and b²; (5) conclusion: same big square, same four triangles, so c² = a² + b², with the equation written large. Up to ~16 words on screen is fine for this one; keep labels ≥ 40px. Geometry must be mathematically correct (use one consistent a=3, b=4, c=5 scale).