diff --git a/.claude/skills/release/SKILL.md b/.claude/skills/release/SKILL.md
index e052ec2..2b1dddc 100644
--- a/.claude/skills/release/SKILL.md
+++ b/.claude/skills/release/SKILL.md
@@ -2,7 +2,7 @@
 name: release
 description: Release a new version of Simpl-Resultat (bump, changelog, tag, push)
 user-invocable: true
-updated: 2026-07-01
+updated: 2026-07-13
 ---
 
 # /release — Release Simpl-Resultat
@@ -15,6 +15,7 @@ updated: 2026-07-01
 
 ## Workflow
 
+0. **Pré-vol — revalider le tip localement.** `check.yml` ne tourne pas sur `main` : le tip mergé n'a jamais été vu par le CI (le dernier run vert portait sur la branche d'issue avant merge), et le tag grave ce tip exact dans des binaires distribués. Lancer `npm run build && npm test` (vitest) + `cd src-tauri && cargo check && cargo test`. Vérifier aussi que `.claude/worktrees/` est vide (worktrees leftover → vitest récurse et gonfle le compteur). Ne tagger que sur un tip vert.
 1. Determiner la nouvelle version (argument utilisateur ou demander)
 2. Bump version dans les 5 fichiers :
    - `src-tauri/Cargo.toml` (ligne `version = "..."`)
@@ -37,6 +38,9 @@ updated: 2026-07-01
    ```
 7. Push : `git push origin main && git push origin vX.Y.Z`
 8. Forgejo CI build automatique (Windows + Linux) via `release.yml` sur `on: push: tags: v*`
+9. **Post-CI — vérifier la release publiée.** Surveiller `release.yml` (outil `Monitor` sur le run), puis vérifier la release réellement attachée — `status=success` du workflow ne suffit pas :
+   - Les **7 artefacts** attendus : `.exe` NSIS, `.deb`, `.rpm`, leurs 3 signatures `.sig`, et `latest.json`.
+   - Le contenu de `latest.json` (il pilote l'auto-update des installations existantes) : champ `version` correct, signatures non vides pour les deux plateformes, URLs pointant vers les bons binaires, notes extraites du CHANGELOG.
 
 ## Regles
 
@@ -45,7 +49,9 @@ updated: 2026-07-01
 - Format Keep a Changelog : `## [X.Y.Z] - YYYY-MM-DD`
 - Les changelogs sont bundles dans `public/` pour l'affichage in-app
 - Tag **annote** (`-a`), pas lightweight : les artefacts CI reference le tag pour les release notes
+- **Tagger publie vers l'extérieur** : `release.yml` pousse le JSON d'updater, donc les utilisateurs installés reçoivent la mise à jour automatiquement. Confirmer avec Max avant de tagger.
 
 ## Changelog
 - 2026-04-19 — Added Cargo.lock + package-lock.json to bump list, `npm install --package-lock-only` fallback when lockfile stale, explicit `[Unreleased]` migration pattern, annotated tags (#102/#112 release cycle)
 - 2026-07-01 — Documenter que le header FR est `## [Non publié]` (≠ `[Unreleased]`), pour éviter le faux diagnostic « changelog FR vide » lors de la migration. Source : session 5466da98.
+- 2026-07-13 — Étape 0 (pré-vol) : revalider le tip localement avant de tagger — `check.yml` ne tourne pas sur `main`, le tip mergé n'a jamais été vu par le CI ; vérifier `.claude/worktrees/` vide (vitest récurse sinon). Étape 9 (post-CI) : vérifier la release publiée — 7 artefacts attendus + contenu de `latest.json` (pilote l'auto-update) ; `status=success` ne suffit pas. Règle : tagger publie vers l'extérieur (updater automatique) → confirmer avec Max avant de tagger. Source : session fdda84cb (release v0.13.0).
diff --git a/CHANGELOG.fr.md b/CHANGELOG.fr.md
index 1a34346..7c0ae1c 100644
--- a/CHANGELOG.fr.md
+++ b/CHANGELOG.fr.md
@@ -2,6 +2,10 @@
 
 ## [Non publié]
 
+### Modifié
+
+- Rapports : les trois tableaux de rapport hiérarchiques (Comparaison réel-vs-réel, réel-vs-budget, et Tendances par catégorie) permettent désormais de **replier ou déplier chaque niveau de la hiérarchie de catégories**, plus seulement le premier. Chaque catégorie parente — y compris les intermédiaires — porte son propre chevron ; en déplier une révèle ses enfants directs (eux-mêmes repliés), pour descendre un niveau à la fois. Les tableaux s'ouvrent entièrement repliés (seules les catégories de premier niveau visibles), « Tout déplier » ouvre tous les niveaux d'un coup, et vos choix de repli sont désormais enregistrés **par profil** — dans la base de données du profil, donc détruits avec lui — au lieu du navigateur. Les sous-totaux et les lignes de résultat restent rigoureusement inchangés quel que soit ce que vous repliez (#288).
+
 ## [0.13.0] - 2026-07-12
 
 ### Ajouté
diff --git a/CHANGELOG.md b/CHANGELOG.md
index baa699f..9131ae0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Changed
+
+- Reports: the three hierarchical report tables (real-vs-real Compare, real-vs-budget Compare, and Trends by category) now let you **collapse or expand every level of the category hierarchy**, not just the top level. Every parent category — including the intermediate ones — carries its own chevron; expanding one reveals its direct children (themselves collapsed), so you drill down one level at a time. The tables open fully collapsed (only the top-level categories visible), "Expand all" opens every level at once, and your collapse choices are now saved **per profile** — in the profile's own database, so they are destroyed with the profile — instead of in the browser. Subtotals and result lines stay exactly the same whatever you fold away (#288).
+
 ## [0.13.0] - 2026-07-12
 
 ### Added
diff --git a/src/components/reports/BudgetVsActualTable.tsx b/src/components/reports/BudgetVsActualTable.tsx
index bd8f1b0..2257db5 100644
--- a/src/components/reports/BudgetVsActualTable.tsx
+++ b/src/components/reports/BudgetVsActualTable.tsx
@@ -29,11 +29,11 @@ interface BudgetVsActualTableProps {
 
 const STORAGE_KEY = "subtotals-position";
 
-// Collapse groups keyed by category id; depth mirrors the render logic below
-// (a missing depth is derived from parent_id) so hidden rows are exactly a
-// group's indented descendants.
+// Collapse groups keyed by category id; a row is hidden when any ancestor
+// (walking parent_id) is collapsed, so every parent level is collapsible.
 const BVA_COLLAPSE_ACCESSORS: CollapseAccessors<BudgetVsActualRow> = {
-  keyOf: (row) => String(row.category_id),
+  keyOf: (row) => `p:${row.category_id}`,
+  parentKeyOf: (row) => (row.parent_id != null ? `p:${row.parent_id}` : null),
   depthOf: (row) => row.depth ?? (row.parent_id !== null && !row.is_parent ? 1 : 0),
   isParent: (row) => row.is_parent,
 };
@@ -116,11 +116,12 @@ export default function BudgetVsActualTable({ data }: BudgetVsActualTableProps)
           const depth = row.depth ?? (row.parent_id !== null && !row.is_parent ? 1 : 0);
           const isTopParent = isParent && depth === 0;
           const isIntermediateParent = isParent && depth >= 1;
-          const collapsed = isTopParent && groups.isCollapsed(row);
+          const collapsed = isParent && groups.isCollapsed(row);
           const paddingClass = depth >= 3 ? "pl-20" : depth === 2 ? "pl-14" : depth === 1 ? "pl-8" : "px-3";
           return (
             <tr
               key={`${row.category_id}-${row.is_parent}-${depth}`}
+              aria-level={isParent ? depth + 1 : undefined}
               className={`border-b border-[var(--border)]/50 ${
                 isTopParent ? "bg-[color-mix(in_srgb,var(--muted)_30%,var(--card))] font-semibold" :
                 isIntermediateParent ? "bg-[color-mix(in_srgb,var(--muted)_15%,var(--card))] font-medium" : ""
@@ -133,7 +134,7 @@ export default function BudgetVsActualTable({ data }: BudgetVsActualTableProps)
                     ? `${paddingClass} bg-[color-mix(in_srgb,var(--muted)_15%,var(--card))]`
                     : `${paddingClass} bg-[var(--card)]`
               }`}>
-                {isTopParent ? (
+                {isParent ? (
                   <button
                     type="button"
                     onClick={() => groups.toggle(row)}
@@ -255,7 +256,7 @@ export default function BudgetVsActualTable({ data }: BudgetVsActualTableProps)
         {hasGroups && (
           <button
             type="button"
-            onClick={() => (allExpanded ? groups.collapseAll() : groups.expandAll(data))}
+            onClick={() => (allExpanded ? groups.collapseAll(data) : groups.expandAll(data))}
             className="inline-flex items-center gap-1.5 px-2.5 py-1 rounded-lg text-xs font-medium text-[var(--muted-foreground)] hover:bg-[var(--muted)] transition-colors"
           >
             {allExpanded ? <ChevronsDownUp size={13} /> : <ChevronsUpDown size={13} />}
diff --git a/src/components/reports/CategoryOverTimeTable.tsx b/src/components/reports/CategoryOverTimeTable.tsx
index 42f9fed..fd7d8f2 100644
--- a/src/components/reports/CategoryOverTimeTable.tsx
+++ b/src/components/reports/CategoryOverTimeTable.tsx
@@ -93,12 +93,13 @@ export default function CategoryOverTimeTable({ data }: CategoryOverTimeTablePro
         const depth = row.depth;
         const isTopParent = isParent && depth === 0;
         const isIntermediateParent = isParent && depth >= 1;
-        const collapsed = isTopParent && groups.isCollapsed(row);
+        const collapsed = isParent && groups.isCollapsed(row);
         const paddingClass =
           depth >= 3 ? "pl-20" : depth === 2 ? "pl-14" : depth === 1 ? "pl-8" : "px-3";
         return (
           <tr
             key={`${row.categoryId ?? "uncat"}-${isParent}-${depth}-${row.categoryName}`}
+            aria-level={isParent ? depth + 1 : undefined}
             className={`border-b border-[var(--border)]/50 ${
               isTopParent
                 ? "bg-[color-mix(in_srgb,var(--muted)_30%,var(--card))] font-semibold"
@@ -116,7 +117,7 @@ export default function CategoryOverTimeTable({ data }: CategoryOverTimeTablePro
                     : `${paddingClass} bg-[var(--card)]`
               }`}
             >
-              {isTopParent ? (
+              {isParent ? (
                 <button
                   type="button"
                   onClick={() => groups.toggle(row)}
@@ -211,7 +212,7 @@ export default function CategoryOverTimeTable({ data }: CategoryOverTimeTablePro
         <div className="flex justify-end items-center gap-1 px-3 py-2 border-b border-[var(--border)]">
           <button
             type="button"
-            onClick={() => (allExpanded ? groups.collapseAll() : groups.expandAll(data.tree))}
+            onClick={() => (allExpanded ? groups.collapseAll(data.tree) : groups.expandAll(data.tree))}
             className="inline-flex items-center gap-1.5 px-2.5 py-1 rounded-lg text-xs font-medium text-[var(--muted-foreground)] hover:bg-[var(--muted)] transition-colors"
           >
             {allExpanded ? <ChevronsDownUp size={13} /> : <ChevronsUpDown size={13} />}
diff --git a/src/components/reports/CategoryTable.tsx b/src/components/reports/CategoryTable.tsx
deleted file mode 100644
index c7e653a..0000000
--- a/src/components/reports/CategoryTable.tsx
+++ /dev/null
@@ -1,74 +0,0 @@
-import { useTranslation } from "react-i18next";
-import type { CategoryBreakdownItem } from "../../shared/types";
-
-const cadFormatter = (value: number) =>
-  new Intl.NumberFormat("en-CA", { style: "currency", currency: "CAD", maximumFractionDigits: 0 }).format(value);
-
-interface CategoryTableProps {
-  data: CategoryBreakdownItem[];
-  hiddenCategories?: Set<string>;
-}
-
-export default function CategoryTable({ data, hiddenCategories }: CategoryTableProps) {
-  const { t } = useTranslation();
-
-  const visibleData = hiddenCategories?.size
-    ? data.filter((d) => !hiddenCategories.has(d.category_name))
-    : data;
-
-  if (visibleData.length === 0) {
-    return (
-      <div className="bg-[var(--card)] border border-[var(--border)] rounded-xl p-8 text-center text-[var(--muted-foreground)]">
-        {t("dashboard.noData")}
-      </div>
-    );
-  }
-
-  const grandTotal = visibleData.reduce((sum, row) => sum + row.total, 0);
-
-  return (
-    <div className="bg-[var(--card)] border border-[var(--border)] rounded-xl overflow-hidden">
-      <div className="overflow-x-auto overflow-y-auto" style={{ maxHeight: "calc(100vh - 220px)" }}>
-        <table className="w-full text-sm">
-          <thead className="sticky top-0 z-20">
-            <tr className="border-b border-[var(--border)] bg-[var(--card)]">
-              <th className="text-left px-3 py-2 font-medium text-[var(--muted-foreground)] bg-[var(--card)]">
-                {t("budget.category")}
-              </th>
-              <th className="text-right px-3 py-2 font-medium text-[var(--muted-foreground)] bg-[var(--card)]">
-                {t("common.total")}
-              </th>
-              <th className="text-right px-3 py-2 font-medium text-[var(--muted-foreground)] bg-[var(--card)]">
-                %
-              </th>
-            </tr>
-          </thead>
-          <tbody>
-            {visibleData.map((row) => (
-              <tr key={row.category_id ?? "uncategorized"} className="border-b border-[var(--border)]/50">
-                <td className="px-3 py-1.5">
-                  <span className="flex items-center gap-2">
-                    <span
-                      className="w-2.5 h-2.5 rounded-full shrink-0"
-                      style={{ backgroundColor: row.category_color }}
-                    />
-                    {row.category_name}
-                  </span>
-                </td>
-                <td className="text-right px-3 py-1.5">{cadFormatter(row.total)}</td>
-                <td className="text-right px-3 py-1.5 text-[var(--muted-foreground)]">
-                  {grandTotal !== 0 ? `${((row.total / grandTotal) * 100).toFixed(1)}%` : "—"}
-                </td>
-              </tr>
-            ))}
-            <tr className="border-t-2 border-[var(--border)] font-bold text-sm bg-[var(--muted)]/20">
-              <td className="px-3 py-3">{t("common.total")}</td>
-              <td className="text-right px-3 py-3">{cadFormatter(grandTotal)}</td>
-              <td className="text-right px-3 py-3 text-[var(--muted-foreground)]">100%</td>
-            </tr>
-          </tbody>
-        </table>
-      </div>
-    </div>
-  );
-}
diff --git a/src/components/reports/ComparePeriodTable.tsx b/src/components/reports/ComparePeriodTable.tsx
index e77b70c..483371b 100644
--- a/src/components/reports/ComparePeriodTable.tsx
+++ b/src/components/reports/ComparePeriodTable.tsx
@@ -59,10 +59,11 @@ function deltaColor(value: number, higherIsBetter: boolean): string {
 
 const STORAGE_KEY = "compare-subtotals-position";
 
-// Collapse groups keyed by category id; depth/parent mirror the render logic
-// below so the hidden rows are exactly a group's indented descendants.
+// Collapse groups keyed by category id; a row is hidden when any ancestor
+// (walking parent_id) is collapsed, so every parent level is collapsible.
 const COMPARE_COLLAPSE_ACCESSORS: CollapseAccessors<CategoryDelta> = {
-  keyOf: (row) => String(row.categoryId),
+  keyOf: (row) => `p:${row.categoryId}`,
+  parentKeyOf: (row) => (row.parent_id != null ? `p:${row.parent_id}` : null),
   depthOf: (row) => row.depth ?? 0,
   isParent: (row) => row.is_parent ?? false,
 };
@@ -154,12 +155,13 @@ export default function ComparePeriodTable({
           const depth = row.depth ?? 0;
           const isTopParent = isParent && depth === 0;
           const isIntermediateParent = isParent && depth >= 1;
-          const collapsed = isTopParent && groups.isCollapsed(row);
+          const collapsed = isParent && groups.isCollapsed(row);
           const paddingClass =
             depth >= 3 ? "pl-20" : depth === 2 ? "pl-14" : depth === 1 ? "pl-8" : "px-3";
           return (
             <tr
               key={`${row.categoryId ?? "uncat"}-${isParent}-${depth}-${row.categoryName}`}
+              aria-level={isParent ? depth + 1 : undefined}
               className={`border-b border-[var(--border)]/50 ${
                 isTopParent
                   ? "bg-[color-mix(in_srgb,var(--muted)_30%,var(--card))] font-semibold"
@@ -177,7 +179,7 @@ export default function ComparePeriodTable({
                       : `${paddingClass} bg-[var(--card)]`
                 }`}
               >
-                {isTopParent ? (
+                {isParent ? (
                   <button
                     type="button"
                     onClick={() => groups.toggle(row)}
@@ -349,7 +351,7 @@ export default function ComparePeriodTable({
         {hasGroups && (
           <button
             type="button"
-            onClick={() => (allExpanded ? groups.collapseAll() : groups.expandAll(rows))}
+            onClick={() => (allExpanded ? groups.collapseAll(rows) : groups.expandAll(rows))}
             className="inline-flex items-center gap-1.5 px-2.5 py-1 rounded-lg text-xs font-medium text-[var(--muted-foreground)] hover:bg-[var(--muted)] transition-colors"
           >
             {allExpanded ? <ChevronsDownUp size={13} /> : <ChevronsUpDown size={13} />}
diff --git a/src/components/reports/overTimeTableModel.test.ts b/src/components/reports/overTimeTableModel.test.ts
index 04073eb..eae9d05 100644
--- a/src/components/reports/overTimeTableModel.test.ts
+++ b/src/components/reports/overTimeTableModel.test.ts
@@ -45,23 +45,26 @@ function makeData(months: string[], tree: OverTimeRow[]): CategoryOverTimeData {
 
 const MONTHS = ["2025-01", "2025-02"];
 
-// A realistic parent-first depth-first tree (income → expense → transfer):
+// A realistic parent-first depth-first tree, three levels deep on the expense
+// side (income → expense → transfer):
 //   Revenus (parent, id 1)
-//     Paie      (leaf, id 11)
-//     Bonus     (leaf, id 12)
+//     Paie          (leaf, id 11)
+//     Bonus         (leaf, id 12)
 //   Dépenses (parent, id 2)
-//     Épicerie  (leaf, id 21)
-//     Resto     (leaf, id 22)
-//   Loyer     (top-level leaf, id 23)
-//   Épargne   (transfer leaf, id 3)
+//     Alimentation  (INTERMEDIATE parent, id 20)
+//       Épicerie    (leaf, id 21)
+//       Resto       (leaf, id 22)
+//   Loyer           (top-level leaf, id 23)
+//   Épargne         (transfer leaf, id 3)
 function buildTree(): OverTimeRow[] {
   return [
     mkRow(1, "Revenus", [3000, 3500], "income", { is_parent: true, depth: 0 }),
     mkRow(11, "Paie", [3000, 3000], "income", { parent_id: 1, depth: 1 }),
     mkRow(12, "Bonus", [0, 500], "income", { parent_id: 1, depth: 1 }),
     mkRow(2, "Dépenses", [500, 800], "expense", { is_parent: true, depth: 0 }),
-    mkRow(21, "Épicerie", [400, 600], "expense", { parent_id: 2, depth: 1 }),
-    mkRow(22, "Resto", [100, 200], "expense", { parent_id: 2, depth: 1 }),
+    mkRow(20, "Alimentation", [500, 800], "expense", { is_parent: true, parent_id: 2, depth: 1 }),
+    mkRow(21, "Épicerie", [400, 600], "expense", { parent_id: 20, depth: 2 }),
+    mkRow(22, "Resto", [100, 200], "expense", { parent_id: 20, depth: 2 }),
     mkRow(23, "Loyer", [1000, 1000], "expense", { depth: 0 }),
     mkRow(3, "Épargne", [200, 200], "transfer", { depth: 0 }),
   ];
@@ -70,6 +73,7 @@ function buildTree(): OverTimeRow[] {
 const acc = OVERTIME_COLLAPSE_ACCESSORS;
 /** Mirrors the hook: a group is collapsed unless its key is in the expanded set. */
 const isCollapsed = (expanded: Set<string>) => (row: OverTimeRow) => !expanded.has(acc.keyOf(row));
+const names = (rows: OverTimeRow[]) => rows.map((r) => r.categoryName);
 
 describe("overTimeTableModel — storage key", () => {
   it("uses a trends-specific key, distinct from the comparable tables", () => {
@@ -79,13 +83,18 @@ describe("overTimeTableModel — storage key", () => {
 });
 
 describe("overTimeTableModel — collapse accessors", () => {
-  it("keys by category id and reads the snake_case hierarchy block", () => {
-    const parent = buildTree()[0];
-    const leaf = buildTree()[1];
-    expect(acc.keyOf(parent)).toBe("1");
-    expect(acc.depthOf(leaf)).toBe(1);
-    expect(acc.isParent(parent)).toBe(true);
-    expect(acc.isParent(leaf)).toBe(false);
+  it("keys parents/leaves injectively (p:<id>) and climbs parent_id", () => {
+    const revenus = buildTree()[0]; // parent
+    const paie = buildTree()[1]; // leaf under Revenus
+    const alimentation = buildTree()[4]; // intermediate parent
+    expect(acc.keyOf(revenus)).toBe("p:1");
+    expect(acc.parentKeyOf(revenus)).toBeNull(); // root
+    expect(acc.parentKeyOf(paie)).toBe("p:1"); // climbs to Revenus
+    expect(acc.parentKeyOf(alimentation)).toBe("p:2"); // climbs to Dépenses
+    expect(acc.depthOf(paie)).toBe(1);
+    expect(acc.isParent(revenus)).toBe(true);
+    expect(acc.isParent(paie)).toBe(false);
+    expect(acc.isParent(alimentation)).toBe(true);
   });
 });
 
@@ -101,12 +110,14 @@ describe("overTimeTableModel.groupOverTimeSections", () => {
 
     // Full hierarchy: the parent row is present (unlike the leaves-only reducer sections).
     const income = nonTransferSections.find((s) => s.type === "income")!;
-    expect(income.rows.map((r) => r.categoryName)).toEqual(["Revenus", "Paie", "Bonus"]);
+    expect(names(income.rows)).toEqual(["Revenus", "Paie", "Bonus"]);
     expect(income.rows[0].is_parent).toBe(true);
 
+    // Expense carries the intermediate parent (Alimentation) too, parent-first.
     const expense = nonTransferSections.find((s) => s.type === "expense")!;
-    expect(expense.rows.map((r) => r.categoryName)).toEqual([
+    expect(names(expense.rows)).toEqual([
       "Dépenses",
+      "Alimentation",
       "Épicerie",
       "Resto",
       "Loyer",
@@ -114,7 +125,7 @@ describe("overTimeTableModel.groupOverTimeSections", () => {
     expect(transferSection?.rows.map((r) => r.categoryName)).toEqual(["Épargne"]);
   });
 
-  it("keeps subtotals as the reducer's leaf sums — a parent is never double-counted", () => {
+  it("keeps subtotals as the reducer's leaf sums — parents (incl. intermediate) are never double-counted", () => {
     const data = makeData(MONTHS, buildTree());
     const analysis = computeOverTimeResults(data);
     const { nonTransferSections } = groupOverTimeSections(analysis, data.tree);
@@ -125,7 +136,8 @@ describe("overTimeTableModel.groupOverTimeSections", () => {
     expect(income.monthly).toEqual({ "2025-01": 3000, "2025-02": 3500 });
 
     const expense = nonTransferSections.find((s) => s.type === "expense")!;
-    // Épicerie 1000 + Resto 300 + Loyer 2000 = 3300 (Dépenses parent excluded).
+    // Épicerie 1000 + Resto 300 + Loyer 2000 = 3300 (Dépenses AND Alimentation
+    // parents excluded, even though Alimentation carries a [500,800] series).
     expect(expense.total).toBe(3300);
   });
 
@@ -148,12 +160,13 @@ describe("overTimeTableModel — collapse behaviour (via visibleRows)", () => {
     const income = nonTransferSections.find((s) => s.type === "income")!;
     const visIncome = visibleRows(income.rows, acc, isCollapsed(new Set()));
     // Revenus stays (its own subtotal row); Paie/Bonus are folded away.
-    expect(visIncome.map((r) => r.categoryName)).toEqual(["Revenus"]);
+    expect(names(visIncome)).toEqual(["Revenus"]);
 
     const expense = nonTransferSections.find((s) => s.type === "expense")!;
     const visExpense = visibleRows(expense.rows, acc, isCollapsed(new Set()));
-    // Dépenses folds its children; the top-level leaf Loyer always stays.
-    expect(visExpense.map((r) => r.categoryName)).toEqual(["Dépenses", "Loyer"]);
+    // Dépenses folds its whole subtree (Alimentation + its leaves); the top-level
+    // leaf Loyer always stays.
+    expect(names(visExpense)).toEqual(["Dépenses", "Loyer"]);
   });
 
   it("reveals Paie (revenue) under Revenus once its group is expanded", () => {
@@ -161,28 +174,55 @@ describe("overTimeTableModel — collapse behaviour (via visibleRows)", () => {
     const { nonTransferSections } = groupOverTimeSections(computeOverTimeResults(data), data.tree);
     const income = nonTransferSections.find((s) => s.type === "income")!;
 
-    const visible = visibleRows(income.rows, acc, isCollapsed(new Set(["1"])));
-    expect(visible.map((r) => r.categoryName)).toEqual(["Revenus", "Paie", "Bonus"]);
+    const visible = visibleRows(income.rows, acc, isCollapsed(new Set(["p:1"])));
+    expect(names(visible)).toEqual(["Revenus", "Paie", "Bonus"]);
     expect(visible.some((r) => r.categoryName === "Paie")).toBe(true);
   });
 
+  it("cascades across three levels: a root reveals only its direct child parent, not the leaves", () => {
+    const data = makeData(MONTHS, buildTree());
+    const { nonTransferSections } = groupOverTimeSections(computeOverTimeResults(data), data.tree);
+    const expense = nonTransferSections.find((s) => s.type === "expense")!;
+
+    // Expand Dépenses only: Alimentation (direct child) shows, Loyer stays, but
+    // Épicerie/Resto (grandchildren under the still-collapsed Alimentation) do NOT.
+    const rootOnly = visibleRows(expense.rows, acc, isCollapsed(new Set(["p:2"])));
+    expect(names(rootOnly)).toEqual(["Dépenses", "Alimentation", "Loyer"]);
+
+    // Expand Dépenses AND Alimentation: the leaves finally appear.
+    const bothOpen = visibleRows(expense.rows, acc, isCollapsed(new Set(["p:2", "p:20"])));
+    expect(names(bothOpen)).toEqual(["Dépenses", "Alimentation", "Épicerie", "Resto", "Loyer"]);
+
+    // Expand the intermediate but NOT the root: a collapsed ancestor wins, nothing
+    // under Dépenses is revealed.
+    const intermediateOnly = visibleRows(expense.rows, acc, isCollapsed(new Set(["p:20"])));
+    expect(names(intermediateOnly)).toEqual(["Dépenses", "Loyer"]);
+  });
+
   it("collapse is purely visual: subtotals, before-transfers and net are unchanged", () => {
     const data = makeData(MONTHS, buildTree());
     const analysis = computeOverTimeResults(data);
     const { nonTransferSections } = groupOverTimeSections(analysis, data.tree);
     const income = nonTransferSections.find((s) => s.type === "income")!;
+    const expense = nonTransferSections.find((s) => s.type === "expense")!;
 
     // Figures come from the raw tree (never the visible rows), so they hold in
     // every collapse state.
     expect(analysis.beforeTransfers.total).toBe(3200); // 6500 income − 3300 expense
     expect(analysis.net.total).toBe(3600); // 3200 + 400 transfer
     expect(income.total).toBe(6500);
+    expect(expense.total).toBe(3300);
 
     // Folding vs expanding a group only changes how many rows are visible.
     const collapsed = visibleRows(income.rows, acc, isCollapsed(new Set()));
-    const expanded = visibleRows(income.rows, acc, isCollapsed(new Set(["1"])));
+    const expanded = visibleRows(income.rows, acc, isCollapsed(new Set(["p:1"])));
     expect(collapsed.length).toBeLessThan(expanded.length);
-    // The subtotal the table shows is identical in both states.
-    expect(income.total).toBe(6500);
+
+    // Expanding the intermediate expense level does not move the section subtotal.
+    const expenseAllOpen = visibleRows(expense.rows, acc, isCollapsed(new Set(["p:2", "p:20"])));
+    expect(expenseAllOpen.length).toBeGreaterThan(
+      visibleRows(expense.rows, acc, isCollapsed(new Set())).length,
+    );
+    expect(expense.total).toBe(3300);
   });
 });
diff --git a/src/components/reports/overTimeTableModel.ts b/src/components/reports/overTimeTableModel.ts
index a0d5cd7..60337fa 100644
--- a/src/components/reports/overTimeTableModel.ts
+++ b/src/components/reports/overTimeTableModel.ts
@@ -10,13 +10,14 @@ import type { OverTimeAnalysis, OverTimeType } from "./overTimeResults";
  */
 
 /**
- * Collapse groups keyed by category id; depth/parent mirror the tree the render
- * indents by, so a collapsed group hides exactly its indented descendants. The
+ * Collapse groups keyed by category id; a row is hidden when any ancestor
+ * (walking parent_id) is collapsed, so every parent level is collapsible. The
  * `OverTimeRow` hierarchy block is snake_case (mirrors `CategoryDelta`), so these
  * accessors compose with `collapsibleRows` / `useCollapsibleGroups` unchanged.
  */
 export const OVERTIME_COLLAPSE_ACCESSORS: CollapseAccessors<OverTimeRow> = {
-  keyOf: (row) => String(row.categoryId),
+  keyOf: (row) => `p:${row.categoryId}`,
+  parentKeyOf: (row) => (row.parent_id != null ? `p:${row.parent_id}` : null),
   depthOf: (row) => row.depth,
   isParent: (row) => row.is_parent,
 };
diff --git a/src/hooks/useCollapsibleGroups.ts b/src/hooks/useCollapsibleGroups.ts
index 8bd58f7..ec1f5b6 100644
--- a/src/hooks/useCollapsibleGroups.ts
+++ b/src/hooks/useCollapsibleGroups.ts
@@ -1,93 +1,133 @@
-import { useCallback, useState } from "react";
+import { useCallback, useEffect, useState } from "react";
 import {
   type CollapseAccessors,
   collapsibleKeys,
+  isCollapsedFor,
   parseStoredExpanded,
   serializeExpanded,
   visibleRows,
 } from "../utils/collapsibleRows";
+import { getPreference, setPreference } from "../services/userPreferenceService";
 
 export interface CollapsibleGroups<T> {
   /** Filters a section's rows down to the ones visible under the current state. */
   visible: (rows: T[]) => T[];
-  /** True when this top-level parent row is collapsed (its children are hidden). */
+  /** True when this parent row is collapsed (its subtree is hidden). */
   isCollapsed: (row: T) => boolean;
   /** Flip one group between collapsed and expanded, then persist. */
   toggle: (row: T) => void;
   /** Expand every collapsible group found in `rows`, then persist. */
   expandAll: (rows: T[]) => void;
-  /** Collapse every group (back to the default), then persist. */
-  collapseAll: () => void;
+  /** Collapse every collapsible group found in `rows`, then persist. */
+  collapseAll: (rows: T[]) => void;
   /** True when `rows` has at least one group and all of them are expanded. */
   allExpanded: (rows: T[]) => boolean;
-  /** Number of collapsible top-level groups in `rows`. */
+  /** Number of collapsible groups (parents, any depth) in `rows`. */
   groupCount: (rows: T[]) => number;
 }
 
 /**
- * Per-report collapse/expand state for the hierarchical comparable tables
- * (issue #254). Groups are collapsed by default (issue #260): the persisted
- * value is the set of *expanded* group keys, so a first-ever visit (empty set)
- * shows every group collapsed with only its subtotal, while any group the user
- * expands is remembered.
+ * Per-report collapse/expand state for the hierarchical tables (issue #254/#265),
+ * generalised to every hierarchy level (issue #288).
  *
- * Persistence uses localStorage, the same synchronous store the sibling
- * "subtotals on top/bottom" toggle already uses in these tables. State is kept
- * per report via a distinct `storageKey`.
+ * The persisted value is the set of keys whose state DIFFERS from the default
+ * (see `isCollapsedFor`), so `defaultExpanded: false` + an empty set = everything
+ * collapsed — the reports' established behaviour — while `defaultExpanded: true`
+ * + an empty set = everything expanded.
+ *
+ * Persistence lives in `user_preferences`, the profile's own SQLite table, so the
+ * state is scoped per profile for free and is destroyed with the profile (no
+ * localStorage residue surviving `deleteProfile` — a privacy-first requirement).
+ * Reads/writes are async; hydration runs in an effect. There is no visible flash
+ * because the default state IS what renders first, and hydration can only reveal
+ * what the user had opened. `storageKey: null` disables persistence entirely
+ * (pure in-memory state, for the category trees).
+ *
+ * The hook stays context-free — it never calls `useProfile()` — because the
+ * `user_preferences` key is already per-profile (it lives in the profile's DB).
  */
 export function useCollapsibleGroups<T>(
-  storageKey: string,
+  storageKey: string | null,
   acc: CollapseAccessors<T>,
+  options?: { defaultExpanded?: boolean },
 ): CollapsibleGroups<T> {
-  const [expanded, setExpanded] = useState<Set<string>>(() =>
-    parseStoredExpanded(
-      typeof localStorage !== "undefined" ? localStorage.getItem(storageKey) : null,
-    ),
-  );
+  const defaultExpanded = options?.defaultExpanded ?? false;
+
+  // Keys whose state differs from the default. Initial = default (empty), then an
+  // effect hydrates from user_preferences when a storageKey is set.
+  const [flipped, setFlipped] = useState<Set<string>>(() => new Set());
+
+  useEffect(() => {
+    if (storageKey === null) {
+      // No persistence: reset to the default state on (re)mount / key change.
+      setFlipped(new Set());
+      return;
+    }
+    let cancelled = false;
+    void getPreference(storageKey)
+      .then((raw) => {
+        if (!cancelled) setFlipped(parseStoredExpanded(raw));
+      })
+      .catch(() => {
+        // Best-effort: a read failure just keeps the default state.
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [storageKey]);
 
   const persist = useCallback(
     (next: Set<string>) => {
-      try {
-        localStorage.setItem(storageKey, serializeExpanded(next));
-      } catch {
-        // Best-effort: a write failure just means the next session falls back
-        // to the collapsed default.
+      setFlipped(next);
+      if (storageKey !== null) {
+        void setPreference(storageKey, serializeExpanded(next)).catch(() => {
+          // Best-effort: a write failure just means the next session falls back
+          // to the default state.
+        });
       }
-      setExpanded(next);
     },
     [storageKey],
   );
 
-  const isCollapsed = useCallback((row: T) => !expanded.has(acc.keyOf(row)), [expanded, acc]);
+  const isCollapsed = useCallback(
+    (row: T) => isCollapsedFor(flipped, acc.keyOf(row), defaultExpanded),
+    [flipped, acc, defaultExpanded],
+  );
 
   const visible = useCallback((rows: T[]) => visibleRows(rows, acc, isCollapsed), [acc, isCollapsed]);
 
   const toggle = useCallback(
     (row: T) => {
       const key = acc.keyOf(row);
-      const next = new Set(expanded);
+      const next = new Set(flipped);
       if (next.has(key)) next.delete(key);
       else next.add(key);
       persist(next);
     },
-    [expanded, acc, persist],
+    [flipped, acc, persist],
   );
 
+  // In `defaultExpanded` polarity the flipped set holds the *collapsed* keys, so
+  // expanding everything means clearing it; collapsing everything means filling
+  // it. The polarity is inverted when the default is collapsed.
   const expandAll = useCallback(
-    (rows: T[]) => persist(new Set(collapsibleKeys(rows, acc))),
-    [acc, persist],
+    (rows: T[]) => persist(defaultExpanded ? new Set() : new Set(collapsibleKeys(rows, acc))),
+    [acc, persist, defaultExpanded],
   );
 
-  const collapseAll = useCallback(() => persist(new Set()), [persist]);
+  const collapseAll = useCallback(
+    (rows: T[]) => persist(defaultExpanded ? new Set(collapsibleKeys(rows, acc)) : new Set()),
+    [acc, persist, defaultExpanded],
+  );
 
   const groupCount = useCallback((rows: T[]) => collapsibleKeys(rows, acc).length, [acc]);
 
   const allExpanded = useCallback(
     (rows: T[]) => {
       const keys = collapsibleKeys(rows, acc);
-      return keys.length > 0 && keys.every((k) => expanded.has(k));
+      return keys.length > 0 && keys.every((k) => !isCollapsedFor(flipped, k, defaultExpanded));
     },
-    [expanded, acc],
+    [flipped, acc, defaultExpanded],
   );
 
   return { visible, isCollapsed, toggle, expandAll, collapseAll, allExpanded, groupCount };
diff --git a/src/utils/collapsibleRows.test.ts b/src/utils/collapsibleRows.test.ts
index d3cc4a7..cd30aed 100644
--- a/src/utils/collapsibleRows.test.ts
+++ b/src/utils/collapsibleRows.test.ts
@@ -1,102 +1,234 @@
 import { describe, it, expect } from "vitest";
 import {
   type CollapseAccessors,
+  MAX_TREE_DEPTH,
   collapsibleKeys,
+  isCollapsedFor,
   parseStoredExpanded,
   serializeExpanded,
   visibleRows,
 } from "./collapsibleRows";
+import { reorderRows } from "./reorderRows";
 
-/** Tiny hierarchy row for the tests: key, depth, is-parent. */
+/** Tiny hierarchy row: id, parent id, is-parent flag, indentation depth. */
 interface Row {
-  k: string;
-  d: number;
-  p: boolean;
+  id: number;
+  parent: number | null;
+  is_parent: boolean;
+  depth: number;
 }
 
 const acc: CollapseAccessors<Row> = {
-  keyOf: (r) => r.k,
-  depthOf: (r) => r.d,
-  isParent: (r) => r.p,
+  keyOf: (r) => `p:${r.id}`,
+  parentKeyOf: (r) => (r.parent === null ? null : `p:${r.parent}`),
+  isParent: (r) => r.is_parent,
+  depthOf: (r) => r.depth,
 };
 
-const row = (k: string, d: number, p: boolean): Row => ({ k, d, p });
+const r = (id: number, parent: number | null, is_parent: boolean, depth: number): Row => ({
+  id,
+  parent,
+  is_parent,
+  depth,
+});
 
-// A two-group tree with one nested sub-group:
-//   Housing (parent, d0)
-//     Rent (leaf, d1)
-//     Utilities (parent, d1)        <- intermediate parent
-//       Power (leaf, d2)
-//   Salary (parent, d0)
-//     Paycheck (leaf, d1)
-//   Misc (leaf, d0)                 <- top-level leaf, not a group
-const tree: Row[] = [
-  row("housing", 0, true),
-  row("rent", 1, false),
-  row("utilities", 1, true),
-  row("power", 2, false),
-  row("salary", 0, true),
-  row("paycheck", 1, false),
-  row("misc", 0, false),
+// A three-level tree (income → expense → transfer shape is irrelevant here; the
+// point is the depth):
+//   Housing (parent, id 1)
+//     Rent (leaf, id 11)
+//     Utilities (INTERMEDIATE parent, id 12)
+//       Power (leaf, id 121)
+//       Water (leaf, id 122)
+//   Salary (parent, id 2)
+//     Paycheck (leaf, id 21)
+//   Misc (top-level leaf, id 3)
+const dfsTree: Row[] = [
+  r(1, null, true, 0), // Housing
+  r(11, 1, false, 1), // Rent
+  r(12, 1, true, 1), // Utilities (intermediate)
+  r(121, 12, false, 2), // Power
+  r(122, 12, false, 2), // Water
+  r(2, null, true, 0), // Salary
+  r(21, 2, false, 1), // Paycheck
+  r(3, null, false, 0), // Misc
 ];
 
-// Default = collapsed: a group is collapsed unless its key is in the expanded set.
-const isCollapsed = (expanded: Set<string>) => (r: Row) => !expanded.has(r.k);
+// The EXACT same tree, emitted level-order (BFS) — the order the budget grid
+// produces. The ancestor-walk must mask identically to the DFS order.
+const bfsTree: Row[] = [
+  r(1, null, true, 0), // Housing
+  r(2, null, true, 0), // Salary
+  r(3, null, false, 0), // Misc
+  r(11, 1, false, 1), // Rent
+  r(12, 1, true, 1), // Utilities
+  r(21, 2, false, 1), // Paycheck
+  r(121, 12, false, 2), // Power
+  r(122, 12, false, 2), // Water
+];
 
-describe("collapsibleRows.visibleRows", () => {
-  it("collapses every group by default (empty expanded set)", () => {
-    const visible = visibleRows(tree, acc, isCollapsed(new Set()));
-    // Only depth-0 rows survive: the two group headers + the top-level leaf.
-    expect(visible.map((r) => r.k)).toEqual(["housing", "salary", "misc"]);
+/** Report polarity: a group is collapsed unless its key is in the expanded set. */
+const isCollapsed = (expanded: Set<string>) => (row: Row) => !expanded.has(acc.keyOf(row));
+const ids = (rows: Row[]) => rows.map((row) => row.id);
+const idSet = (rows: Row[]) => new Set(ids(rows));
+
+describe("collapsibleRows.visibleRows — ancestor-walk visibility", () => {
+  it("collapses every level by default (empty set) ⇒ only roots survive", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set()));
+    // Housing + Salary (root parents) + Misc (root leaf); everything deeper folds.
+    expect(ids(visible)).toEqual([1, 2, 3]);
   });
 
-  it("reveals a group's full subtree (incl. nested sub-groups) when expanded", () => {
-    const visible = visibleRows(tree, acc, isCollapsed(new Set(["housing"])));
-    expect(visible.map((r) => r.k)).toEqual([
-      "housing",
-      "rent",
-      "utilities",
-      "power",
-      "salary",
-      "misc",
-    ]);
+  it("expanding a root reveals ONLY its direct children, not its grandchildren", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set(["p:1"])));
+    // Rent + Utilities appear; Power/Water (grandchildren) stay folded because the
+    // intermediate Utilities is still collapsed.
+    expect(ids(visible)).toEqual([1, 11, 12, 2, 3]);
+    expect(visible.some((row) => row.id === 121)).toBe(false);
+    expect(visible.some((row) => row.id === 122)).toBe(false);
   });
 
-  it("keeps groups independent — expanding one leaves the others collapsed", () => {
-    const visible = visibleRows(tree, acc, isCollapsed(new Set(["salary"])));
-    expect(visible.map((r) => r.k)).toEqual(["housing", "salary", "paycheck", "misc"]);
+  it("expanding a root AND its intermediate reveals the leaves", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set(["p:1", "p:12"])));
+    expect(ids(visible)).toEqual([1, 11, 12, 121, 122, 2, 3]);
   });
 
-  it("shows everything when all groups are expanded", () => {
-    const visible = visibleRows(tree, acc, isCollapsed(new Set(["housing", "salary"])));
-    expect(visible).toHaveLength(tree.length);
+  it("a collapsed ancestor always wins: expanding an intermediate whose root is collapsed reveals nothing", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set(["p:12"])));
+    // Housing is collapsed, so Utilities (and thus Power/Water) stay hidden even
+    // though Utilities itself is expanded.
+    expect(ids(visible)).toEqual([1, 2, 3]);
   });
 
-  it("always keeps a top-level leaf that has no group", () => {
-    const visible = visibleRows(tree, acc, isCollapsed(new Set()));
-    expect(visible.some((r) => r.k === "misc")).toBe(true);
+  it("keeps groups independent — expanding Salary leaves Housing folded", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set(["p:2"])));
+    expect(ids(visible)).toEqual([1, 2, 21, 3]);
+  });
+
+  it("shows every row once all parents are expanded", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set(["p:1", "p:12", "p:2"])));
+    expect(visible).toHaveLength(dfsTree.length);
+  });
+
+  it("BFS (level-order) rows mask IDENTICALLY to DFS rows — the test that would have killed v1", () => {
+    const states: Set<string>[] = [
+      new Set(),
+      new Set(["p:1"]),
+      new Set(["p:1", "p:12"]),
+      new Set(["p:12"]),
+      new Set(["p:2"]),
+      new Set(["p:1", "p:12", "p:2"]),
+    ];
+    for (const expanded of states) {
+      const dfs = idSet(visibleRows(dfsTree, acc, isCollapsed(expanded)));
+      const bfs = idSet(visibleRows(bfsTree, acc, isCollapsed(expanded)));
+      expect(bfs).toEqual(dfs);
+    }
+  });
+
+  it("masking is unchanged when subtotals are moved to the bottom (reorderRows)", () => {
+    const expanded = new Set(["p:1", "p:12"]);
+    const normal = idSet(visibleRows(dfsTree, acc, isCollapsed(expanded)));
+    // Order-independent: run reorder FIRST (subtotals below their children), then
+    // filter. v1's depth-cursor algorithm broke exactly here.
+    const bottomFirst = reorderRows(dfsTree, false);
+    const afterReorder = idSet(visibleRows(bottomFirst, acc, isCollapsed(expanded)));
+    expect(afterReorder).toEqual(normal);
+  });
+
+  it("always keeps a top-level leaf that has no parent", () => {
+    const visible = visibleRows(dfsTree, acc, isCollapsed(new Set()));
+    expect(visible.some((row) => row.id === 3)).toBe(true);
+  });
+});
+
+describe('collapsibleRows.visibleRows — "(direct)" leaf', () => {
+  // A parent that also holds direct transactions: its "(direct)" leaf shares the
+  // parent's category id but is a leaf, and points back at the parent subtotal.
+  const withDirect: Row[] = [
+    r(1, null, true, 0), // Housing subtotal   -> key p:1
+    r(1, 1, false, 1), // Housing (direct)   -> key p:1, parentKey p:1
+    r(11, 1, false, 1), // Rent
+  ];
+
+  it("hides the (direct) leaf when its parent is collapsed", () => {
+    const visible = visibleRows(withDirect, acc, isCollapsed(new Set()));
+    // Only the Housing subtotal (a root) survives.
+    expect(visible).toHaveLength(1);
+    expect(visible[0].is_parent).toBe(true);
+  });
+
+  it("shows the (direct) leaf when its parent is expanded", () => {
+    const visible = visibleRows(withDirect, acc, isCollapsed(new Set(["p:1"])));
+    expect(visible).toHaveLength(3);
+  });
+
+  it("never treats the (direct) leaf as a collapsible group", () => {
+    // Both the subtotal and the (direct) leaf carry key p:1, but only the parent
+    // subtotal is collapsible — the leaf is not a parent.
+    expect(collapsibleKeys(withDirect, acc)).toEqual(["p:1"]);
+  });
+});
+
+describe("collapsibleRows.visibleRows — corrupt / cross-section chains", () => {
+  it("guards a cyclic parent_id with MAX_TREE_DEPTH (no infinite loop)", () => {
+    // A <-> B cycle, with a leaf hanging under A. Neither A nor B is collapsed, so
+    // the walk keeps climbing until the hop guard trips.
+    const cyclic: Row[] = [
+      r(100, 101, true, 0), // A, parent B
+      r(101, 100, true, 1), // B, parent A
+      r(1001, 100, false, 2), // leaf under A
+    ];
+    const visible = visibleRows(cyclic, acc, isCollapsed(new Set(["p:100", "p:101"])));
+    // Terminates and keeps the leaf visible (no collapsed ancestor was found).
+    expect(visible.some((row) => row.id === 1001)).toBe(true);
+    // Sanity: the guard is a finite, positive cap.
+    expect(MAX_TREE_DEPTH).toBeGreaterThan(3);
+  });
+
+  it("keeps a row whose ancestor is absent from the section (child of another type)", () => {
+    // Orphan points at id 999, which is not in these rows.
+    const orphaned: Row[] = [r(55, 999, false, 1)];
+    const visible = visibleRows(orphaned, acc, isCollapsed(new Set()));
+    // Missing ancestor ⇒ visible (better an orphan shown than a row hidden by a
+    // parent that lives in another section).
+    expect(ids(visible)).toEqual([55]);
   });
 });
 
 describe("collapsibleRows.collapsibleKeys", () => {
-  it("lists only top-level parent rows, in order", () => {
-    expect(collapsibleKeys(tree, acc)).toEqual(["housing", "salary"]);
+  it("lists EVERY parent, intermediates included, in encounter order", () => {
+    // Housing (p:1), Utilities (p:12, intermediate), Salary (p:2) — NOT Misc/leaves.
+    expect(collapsibleKeys(dfsTree, acc)).toEqual(["p:1", "p:12", "p:2"]);
   });
 
   it("returns [] when there is no hierarchy", () => {
-    const flat = [row("a", 0, false), row("b", 0, false)];
+    const flat = [r(1, null, false, 0), r(2, null, false, 0)];
     expect(collapsibleKeys(flat, acc)).toEqual([]);
   });
 });
 
+describe("collapsibleRows.isCollapsedFor — polarity", () => {
+  it("defaultExpanded=false: empty set ⇒ collapsed, a flipped key ⇒ expanded", () => {
+    expect(isCollapsedFor(new Set(), "p:1", false)).toBe(true);
+    expect(isCollapsedFor(new Set(["p:1"]), "p:1", false)).toBe(false);
+    expect(isCollapsedFor(new Set(["p:2"]), "p:1", false)).toBe(true);
+  });
+
+  it("defaultExpanded=true: empty set ⇒ expanded, a flipped key ⇒ collapsed", () => {
+    expect(isCollapsedFor(new Set(), "p:1", true)).toBe(false);
+    expect(isCollapsedFor(new Set(["p:1"]), "p:1", true)).toBe(true);
+    expect(isCollapsedFor(new Set(["p:2"]), "p:1", true)).toBe(false);
+  });
+});
+
 describe("collapsibleRows.parseStoredExpanded / serializeExpanded", () => {
-  it("treats absent storage as the collapsed default (empty set)", () => {
+  it("treats absent storage as the default state (empty set)", () => {
     expect(parseStoredExpanded(null).size).toBe(0);
     expect(parseStoredExpanded("").size).toBe(0);
   });
 
   it("parses a JSON string array back into a set", () => {
-    expect([...parseStoredExpanded('["housing","salary"]')].sort()).toEqual(["housing", "salary"]);
+    expect([...parseStoredExpanded('["p:1","p:2"]')].sort()).toEqual(["p:1", "p:2"]);
   });
 
   it("falls back to empty on corrupt or non-array JSON", () => {
@@ -110,7 +242,7 @@ describe("collapsibleRows.parseStoredExpanded / serializeExpanded", () => {
   });
 
   it("round-trips through serialize", () => {
-    const set = new Set(["a", "b"]);
-    expect([...parseStoredExpanded(serializeExpanded(set))].sort()).toEqual(["a", "b"]);
+    const set = new Set(["p:1", "p:12"]);
+    expect([...parseStoredExpanded(serializeExpanded(set))].sort()).toEqual(["p:1", "p:12"]);
   });
 });
diff --git a/src/utils/collapsibleRows.ts b/src/utils/collapsibleRows.ts
index 28dab25..ef61a76 100644
--- a/src/utils/collapsibleRows.ts
+++ b/src/utils/collapsibleRows.ts
@@ -1,71 +1,104 @@
 /**
- * Collapse/expand of top-level category groups in the hierarchical comparable
- * reports (real-vs-real Compare + Budget-vs-Actual) — issue #254.
+ * Collapse/expand of category groups in the hierarchical reports (real-vs-real
+ * Compare, Budget-vs-Actual, trends over time) — issue #254/#265, generalised to
+ * every hierarchy level in issue #288.
  *
  * Pure helpers only; the React state + persistence glue lives in the
  * `useCollapsibleGroups` hook.
  *
- * A "group" is a top-level parent row (depth 0, is_parent). Collapsing it keeps
- * its own subtotal row visible but hides its entire subtree (every following
- * depth ≥ 1 row until the next depth-0 row). Rows must arrive in depth-first
- * order — the order the compare/budget services already emit them in, and the
- * same order `reorderRows` relies on.
+ * Visibility is decided by an ANCESTOR WALK, not by row adjacency: a row is
+ * hidden iff *any* of its ancestors is collapsed. We climb `parentKeyOf` from a
+ * row until we reach a root (null), an ancestor outside this section (⇒ visible),
+ * or a collapsed ancestor (⇒ hidden). This is independent of the order rows
+ * arrive in — the fix for the v1 adjacency algorithm, which assumed a
+ * depth-first order the budget grid (level-ordered) does not emit.
  *
- * The accessors are passed in rather than read off fixed field names so each
- * table can supply the *exact* depth expression it renders with (CategoryDelta
- * uses `depth ?? 0`; BudgetVsActualRow derives a missing depth from
- * `parent_id`). Keeping the collapse depth and the indentation depth identical
- * guarantees the hidden rows are exactly the indented descendants.
+ * The accessors are supplied by each consumer so every table can key + climb the
+ * exact hierarchy it renders. Keys are prefixed `p:` so they are injective: a
+ * parent subtotal row and its own "(direct)" leaf share a category id but the
+ * leaf is never a parent, so only the subtotal is indexed — the leaf simply
+ * carries the parent's key via `parentKeyOf` and is hidden with it.
  */
 
+/**
+ * Cycle guard for the ancestor walk. The standard taxonomy is three levels deep;
+ * this generous finite cap only exists so a corrupt cyclic `parent_id` (DB
+ * corruption) can never loop forever. Any real chain terminates in a few hops.
+ */
+export const MAX_TREE_DEPTH = 64;
+
 /** How the collapse logic reads hierarchy position + identity off a row. */
 export interface CollapseAccessors<T> {
-  /** Stable per-group key (a category id, stringified). */
+  /** Stable per-parent key, injective across the section: `p:<categoryId>`. */
   keyOf: (row: T) => string;
-  /** Indentation depth; 0 = top-level. Must match the rendered indentation. */
-  depthOf: (row: T) => number;
+  /** Key of this row's parent (`p:<parent_id>`), or null at a root. */
+  parentKeyOf: (row: T) => string | null;
   /** True when the row is a group header / subtotal (has children). */
   isParent: (row: T) => boolean;
+  /** Indentation depth; 0 = top-level. Drives indentation + aria-level ONLY. */
+  depthOf: (row: T) => number;
 }
 
 /**
- * Keeps every row that is currently visible given which top-level groups are
- * collapsed. `isCollapsed` is consulted only for top-level parent rows; a
- * collapsed one keeps its own (subtotal) row and drops its whole subtree.
+ * Keeps every row that is currently visible given which groups are collapsed. A
+ * row is dropped iff any ancestor (walking `parentKeyOf`) is collapsed; a missing
+ * ancestor (parent lives in another section) leaves the row visible.
  */
 export function visibleRows<T>(
   rows: T[],
   acc: CollapseAccessors<T>,
   isCollapsed: (row: T) => boolean,
 ): T[] {
-  const out: T[] = [];
-  // While true we are inside a collapsed top-level parent's subtree and drop
-  // every deeper row until the next depth-0 row re-opens the flow.
-  let hidingSubtree = false;
-  for (const row of rows) {
-    if (acc.depthOf(row) === 0) {
-      out.push(row);
-      hidingSubtree = acc.isParent(row) && isCollapsed(row);
-    } else if (!hidingSubtree) {
-      out.push(row);
+  // Index ONLY parents: a "(direct)" leaf shares its parent's category id but is
+  // never a parent itself, so it never clobbers the subtotal it points at.
+  const parents = new Map<string, T>();
+  for (const r of rows) if (acc.isParent(r)) parents.set(acc.keyOf(r), r);
+
+  const hiddenByAncestor = (row: T): boolean => {
+    let key = acc.parentKeyOf(row);
+    let hops = 0;
+    while (key !== null && hops++ < MAX_TREE_DEPTH) {
+      const parent = parents.get(key);
+      if (parent === undefined) return false; // ancestor outside this section → visible
+      if (isCollapsed(parent)) return true;
+      key = acc.parentKeyOf(parent);
     }
-  }
-  return out;
+    return false;
+  };
+
+  return rows.filter((r) => !hiddenByAncestor(r));
 }
 
-/** Keys of every collapsible group (top-level parent rows), in encounter order. */
+/** Keys of every collapsible group (all parent rows, any depth), in encounter order. */
 export function collapsibleKeys<T>(rows: T[], acc: CollapseAccessors<T>): string[] {
   const keys: string[] = [];
   for (const row of rows) {
-    if (acc.depthOf(row) === 0 && acc.isParent(row)) keys.push(acc.keyOf(row));
+    if (acc.isParent(row)) keys.push(acc.keyOf(row));
   }
   return keys;
 }
 
 /**
- * Parses the persisted value into the set of *expanded* group keys. The report
- * default is "everything collapsed" (issue #254/#260), so an absent or corrupt
- * value yields an empty set — i.e. all groups collapsed on a first-ever visit.
+ * Polarity of the collapse state. The persisted Set holds the keys whose state
+ * DIFFERS from the default, which lets one hook serve both polarities without a
+ * seed:
+ *  - `defaultExpanded: false` (reports, budget) ⇒ Set = the *expanded* keys, so
+ *    an empty Set means everything collapsed (the reports' current behaviour).
+ *  - `defaultExpanded: true` (category trees) ⇒ Set = the *collapsed* keys, so an
+ *    empty Set means everything expanded.
+ */
+export function isCollapsedFor(
+  flipped: Set<string>,
+  key: string,
+  defaultExpanded: boolean,
+): boolean {
+  const isFlipped = flipped.has(key);
+  return defaultExpanded ? isFlipped : !isFlipped;
+}
+
+/**
+ * Parses the persisted value into the flipped-key set (see `isCollapsedFor`). An
+ * absent or corrupt value yields an empty set — i.e. the default collapse state.
  */
 export function parseStoredExpanded(raw: string | null): Set<string> {
   if (!raw) return new Set();
@@ -75,12 +108,12 @@ export function parseStoredExpanded(raw: string | null): Set<string> {
       return new Set(parsed.filter((k): k is string => typeof k === "string"));
     }
   } catch {
-    // Corrupt value: fall back to the collapsed default.
+    // Corrupt value: fall back to the default state.
   }
   return new Set();
 }
 
-/** Serialises the set of expanded group keys for persistence. */
-export function serializeExpanded(expanded: Set<string>): string {
-  return JSON.stringify([...expanded]);
+/** Serialises the flipped-key set for persistence. */
+export function serializeExpanded(flipped: Set<string>): string {
+  return JSON.stringify([...flipped]);
 }