Main work content. Narrow the window below ~60rem to hide the app sidebar; narrow this panel (not possible here, but in a real split pane) to collapse the inner filter sidebar.
App shell
The desktop SaaS layout — sticky topbar, persistent sidebar, scrolling main work area — in @layer porchlight.layout. This is the one place the framework uses a viewport media query: below 60rem the sidebar drops out so the work surface stays usable. The main region is also a query container, so any .pl-l-sidebar nested inside it collapses at narrow app widths without a manual wrapper.
or narrow the window below 60rem to auto-hide it