Builds box-shadow values either from the fields — a single custom layer, Tailwind-like soft/medium/large/inset presets, a smooth multi-layer shadow whose offsets double per layer while opacity fades, or a neumorphic pair derived from a surface colour — or by parsing the layers you type. Output is a CSS rule, a Tailwind arbitrary value, a custom property and the filter: drop-shadow() equivalent. The preview shows the shadow on light and dark surfaces. Everything runs locally.