How it works
Color stores RGBA in 0–1 space. Color.fromHex() parses hex strings. toHSL() decomposes to hue (0–360°), saturation, and lightness. The canvas shows a hue wheel built entirely from Color.fromHSL(h, 0.85, 0.55) — one colour per degree — with the lerped result in the centre and a gradient strip at the bottom.