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+# Responsive Master/Detail for Vocabularies, Search, Fields — Design
+
+**Date:** 2026-06-09
+**Status:** Approved (brainstorming) — ready for implementation planning.
+**Issue:** #58 (master/detail + sidebar layout has no responsive/small-screen handling — remaining half).
+
+## Context
+
+#58 is partially done (commit `0a88a86`, #44): the sidebar collapses to an icon rail, the **Objects** master/detail
+is responsive (wide right-pane / narrow Base UI `Drawer`), and a reusable `lib/use-media-query.ts` exists. The
+**remaining** master/detail screens still use fixed `grid-cols-[20rem_1fr]` / `[24rem_1fr]` with no breakpoints —
+`vocabularies-page.tsx`, `search-page.tsx`, `fields-page.tsx` — so on a small laptop / tablet / split window the
+fixed list + sidebar leave a cramped detail pane, and below ~640px the panes can't coexist.
+
+**Decision (brainstorming): keep the wide side-by-side layout (it's useful for curators); fix only narrow.** Reuse
+one shared drawer + the existing `useMediaQuery` hook. Breakpoint **1024px (`lg`)**, matching Objects. Authorities
+is single-pane → no change. The "resizable splitter" the issue *suggests considering* is out of scope.
+
+The three pages differ: vocabularies + search are **route-driven** (`<Outlet/>`, an index-prompt route + `:id`);
+fields is **`useState`-driven** (FieldList → FieldForm, with the form always present for "create").
+
+## Components
+
+### 1. `components/detail-drawer.tsx` (new) — generalize the Objects drawer
+Today `objects/object-detail-drawer.tsx` is objects-specific (Base UI `Drawer` + close button + a hardcoded
+`<Outlet/>`). Generalize to a reusable component taking `children` + `ariaLabel`:
+```tsx
+import type { ReactNode } from "react";
+import { useTranslation } from "react-i18next";
+import { X } from "lucide-react";
+
+import { Drawer, DrawerClose, DrawerContent } from "@/components/ui/drawer";
+import { Button } from "@/components/ui/button";
+
+/** A right-sliding Base UI Drawer for a master/detail "detail" on narrow viewports. */
+export function DetailDrawer({
+  open,
+  onClose,
+  ariaLabel,
+  children,
+}: {
+  open: boolean;
+  onClose: () => void;
+  ariaLabel: string;
+  children: ReactNode;
+}) {
+  const { t } = useTranslation();
+  return (
+    <Drawer open={open} onOpenChange={(next) => { if (!next) onClose(); }} swipeDirection="right">
+      <DrawerContent aria-label={ariaLabel}>
+        <div className="flex justify-end border-b p-2">
+          <DrawerClose aria-label={t("actions.closeDetail")} render={<Button variant="ghost" size="icon-sm" />}>
+            <X className="size-4" aria-hidden="true" />
+          </DrawerClose>
+        </div>
+        <div className="flex-1 overflow-auto">{children}</div>
+      </DrawerContent>
+    </Drawer>
+  );
+}
+```
+- Delete `objects/object-detail-drawer.tsx`.
+- **Drop the `lazy()`/`Suspense`** that objects-page used to wrap the drawer: it kept Base UI's drawer code out of
+  the entry chunk, but #67 already split `@base-ui/react` into its own `base-ui` vendor chunk (loaded app-wide via
+  the menu/select/etc.), so the lazy boundary no longer saves anything. `DetailDrawer` is a normal import.
+- The close-button label keeps the existing generic `actions.closeDetail` key.
+
+### 2. `vocab/vocabularies-page.tsx` + `search/search-page.tsx` — `useMediaQuery` + route drawer
+Mirror the Objects pattern. Add `useMediaQuery("(min-width: 1024px)")` (`isWide`) and a `useMatch` for the detail
+route (`"/vocabularies/:id"` / `"/search/:id"`), `open = Boolean(match)`, `close = () => navigate("/vocabularies")`
+(resp. `"/search"`).
+- **Wide:** the current side-by-side grid with `<Outlet/>` inline (prompt when no `:id`, detail when selected) —
+  unchanged.
+- **Narrow:** the master full-width (`VocabularyList` / `SearchPanel` under the existing `PageTitle`), plus
+  `{open && <DetailDrawer open={open} onClose={close} ariaLabel={…}><Outlet/></DetailDrawer>}`. With no `:id`, just
+  the master (the index-prompt is a wide-only affordance).
+- Drawer `ariaLabel`: vocabularies → `t("vocab.terms")` ("Terms"); search → `t("objects.detailTitle")` ("Object
+  detail", since a search result's detail IS an object). **No new i18n keys.**
+- The `<Outlet/>` is rendered in exactly one place per branch (the `isWide` ternary), so no double-mount.
+
+### 3. `fields/fields-page.tsx` — pure-CSS responsive stack
+`fields-page` is `useState`-driven and its right pane is *always* a form (create when nothing selected), so a
+drawer would need a new "New field" trigger. Instead make it a responsive **stack** (the issue comment explicitly
+allows "or stack"): change the grid container from `grid grid-cols-[20rem_1fr]` to
+`grid grid-cols-1 lg:grid-cols-[20rem_1fr]`, and give the form pane a top border that only shows when stacked
+(`border-t lg:border-t-0`) while the list keeps its `border-r` (which reads as a bottom divider when stacked — or
+add `border-b lg:border-b-0 lg:border-r` for a clean stacked divider). No JS, no drawer, no new trigger, no
+element duplication — the same `FieldForm` reflows from below the list (narrow) to beside it (wide).
+
+### 4. `objects/objects-page.tsx` — retrofit onto `DetailDrawer`
+Replace the `lazy(ObjectDetailDrawer)` import + `<Suspense>` with a direct `DetailDrawer` import; in the narrow
+branch render `{open && <DetailDrawer open={open} onClose={closeDetail} ariaLabel={t("objects.detailTitle")}><Outlet/></DetailDrawer>}`.
+Behavior-preserving — its existing "narrow: detail renders inside a portaled drawer" test stays green.
+
+## Data flow / behaviour
+No data/routing changes. Each page picks layout via `useMediaQuery("(min-width:1024px)")` (vocab/search/objects) or
+pure CSS (fields). The detail content is identical to today; only its container (inline pane vs Drawer) changes by
+width. The detail route/state, breadcrumbs, and titles are unchanged.
+
+## Error handling / edges
+- `useMediaQuery` is SSR-safe (returns `false` server-side / pre-mount → narrow-first, then corrects on mount).
+- Drawer `open` is derived from the route match (`:id`) / nothing on the index, so the Outlet only has content when
+  open; rendering `{open && <DetailDrawer …>}` mounts it only when active (matches the current objects behaviour).
+- Fields stack: `FieldList` is `overflow-hidden` in a `grid-cols-1` row — ensure the stacked list has a sensible
+  height (it's in a flex/grid row that can scroll); the form below scrolls in its own pane. Keep each pane's
+  `overflow` as today.
+- Drawer accessible name comes from `ariaLabel` (required prop) so every detail drawer is a named dialog (the #62
+  a11y fix, preserved + generalized).
+
+## Testing
+- **`components/detail-drawer.test.tsx`** (new): with `open`, the children render inside a dialog whose accessible
+  name is the `ariaLabel`; clicking the close button (labelled `actions.closeDetail`) calls `onClose`.
+- **`vocab/vocabularies-page` + `search/search-page` tests** (new or extended): reuse the `setViewport(wide)`
+  matchMedia mock from `objects-page.test.tsx`. Narrow + a `:id` route → the detail renders in a portaled drawer
+  (`getByRole("dialog", { name })` within `document.body`); wide + `:id` → the detail is the inline pane (no
+  dialog). Closing the drawer navigates back to the index route.
+- **`fields/fields-page` test**: the grid container carries the responsive classes (`grid-cols-1` +
+  `lg:grid-cols-[20rem_1fr]`); both the list and the form render (jsdom can't measure layout, so assert structure).
+- **`objects/objects-page` tests**: stay green unchanged (the drawer is now the shared `DetailDrawer`).
+- **Gate:** `typecheck`/`lint`/`test`/`build`/`check:size`/`check:colors` green; no new dependency; no new i18n
+  keys; no codename; en/sv parity unaffected. `check:size` unchanged-or-smaller (dropping the objects drawer's
+  separate lazy chunk folds it into base-ui).
+
+## Acceptance criteria
+1. `components/detail-drawer.tsx` exists (Base UI drawer + close button + `children`/`ariaLabel`); `object-detail-drawer.tsx`
+   is deleted; Objects uses the shared `DetailDrawer` (no `lazy`/`Suspense`); its tests stay green.
+2. Vocabularies + Search: wide = current side-by-side (unchanged); narrow (<1024) = master full-width + the detail
+   in a `DetailDrawer` when a `:id` is active; close returns to the index route.
+3. Fields: responsive grid (`grid-cols-1 lg:grid-cols-[20rem_1fr]`) — stacked on narrow, side-by-side on wide.
+4. New tests for `DetailDrawer`, vocabularies-page, search-page (narrow drawer + wide pane), fields-page (responsive
+   structure); all existing tests pass unchanged.
+5. `typecheck`/`lint`/`build`/`check:colors` green; `check:size` reported (unchanged-or-smaller); no new
+   dependency; no new i18n keys; no codename.
+
+## Out of scope → follow-ups
+- A resizable master/detail splitter (issue "consider"); a per-user pane-width preference.
+- Converting `fields` to a route-driven master/detail (it stays `useState`-driven + stacked).