Defines the grid from track templates (a count, or any track list such as 200px 1fr 1fr or repeat(auto-fit, minmax(240px, 1fr))), gaps, item alignment and auto-flow, and optionally names areas from the ASCII rows in the editor — each area is checked to be a rectangle and the column count must match. Output is the container CSS with grid-template-areas and one grid-area class per name (or numbered cells), a Tailwind equivalent and an HTML skeleton; the preview shows the layout. Everything runs locally.