Container Queries and Focus Management Fixes for Resilient TailwindCSS v4 Components

A developer integrating meta/astryx into a production TypeScript stack found that cards broke inside narrow sidebars and widgets because viewport-based breakpoints ignored available container space. Switching to TailwindCSS v4 container queries let components adapt to their own container width instead of the screen size. The same effort exposed modal focus problems, where screen reader and keyboard users could tab into background content, which Radix primitives addressed with built-in focus trapping. The article also covers animation setup and container context placement at the layout boundary, and notes that container queries and Radix each carry performance or bundle-size trade-offs.