M3 — Responsive depth (maxWidth, row wrap, master-detail)

[ajianaz]

Goal

Deepen breakpoint-driven responsiveness so layouts feel native on desktop/tablet.

Tasks

• maxWidth + content-centering for cards & body on desktop (readable line length)
• row wrap mode — auto-flow children to next line when cramped
• Navigation-shell guidance sample (master-detail on desktop, tabs on tablet, stack on mobile)
• Document breakpoint-driven grid hints (mobileColumns/tabletColumns/desktopColumns) with examples

Acceptance

• A single JSON layout renders well across phone, tablet fold, and desktop widths.