Per-cell custom borders (KPI)

Editable KPI scorecard. spreadsheetLayout paints HOT-style per-edge custom borders via an absolute-positioned overlay (no border-collapse conflicts). Edit any quarter or target - the borders re-derive: green double = beat target, blue solid = hit, amber dotted = near miss, red dashed = bad miss; row champion gets a colored full frame.

A live, editable Svelte 5 data grid example. Open the interactive demo or read the documentation.