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+---
+phase: 4
+slug: folders-sharing-quotas-document-ux
+status: draft
+shadcn_initialized: false
+preset: none
+created: 2026-05-25
+---
+
+# Phase 4 — UI Design Contract
+
+> Visual and interaction contract for Phase 4: Folders, Sharing, Quotas & Document UX.
+> Generated by gsd-ui-researcher, verified by gsd-ui-checker.
+> Source: existing codebase scan + 04-CONTEXT.md decisions.
+
+---
+
+## Design System
+
+| Property | Value |
+|----------|-------|
+| Tool | none |
+| Preset | not applicable |
+| Component library | none (inline SVG icons, Tailwind utility classes only) |
+| Icon library | Inline SVG (Heroicons stroke style, w-4 h-4 / w-5 h-5) — do not add an icon package |
+| Font | System font stack (Tailwind default — no custom font loaded) |
+
+No design system change for Phase 4. All new components extend the existing Tailwind utility pattern established in Phase 2/3.
+
+---
+
+## Spacing Scale
+
+Declared values (multiples of 4 only). Source: existing component scan — `p-4`, `px-6 py-5`, `gap-3`, `px-3 py-2`.
+
+| Token | Value | Usage |
+|-------|-------|-------|
+| xs | 4px | Icon gaps, topic badge gaps (`gap-1`) |
+| sm | 8px | Compact element spacing, inline button padding (`py-1.5`) |
+| md | 16px | Default element spacing, card padding (`p-4`) |
+| lg | 24px | Section padding (`px-6 py-5`), page section breaks |
+| xl | 32px | Page content padding (`p-8`) |
+| 2xl | 48px | Major empty-state vertical padding (`py-12`) |
+| 3xl | 64px | Not used in Phase 4 |
+
+Exceptions:
+- Touch targets (icon-only buttons): minimum 44px height enforced via `min-h-[44px]` (established in ConfirmBlock.vue — apply to all icon-only action buttons in this phase).
+- Breadcrumb segment gap: 8px (`gap-2`) with a separator chevron (SVG, w-3 h-3).
+- Modal overlay: full-viewport fixed overlay `inset-0`, modal panel `max-w-md w-full` centered with `p-6` internal padding.
+- Breadcrumb truncation ellipsis button: `px-1 py-0.5` compact.
+
+---
+
+## Typography
+
+Extend existing scale — do not introduce new sizes. Source: DocumentCard.vue, AppSidebar.vue, DocumentView.vue.
+
+| Role | Size | Weight | Line Height | Tailwind classes |
+|------|------|--------|-------------|-----------------|
+| Page heading | 24px (text-2xl) | 700 (font-bold) | 1.2 | `text-2xl font-bold text-gray-900` |
+| Section heading | 18px (text-lg) | 600 (font-semibold) | 1.3 | `text-lg font-semibold text-gray-800` |
+| Body / card label | 14px (text-sm) | 500 (font-medium) | 1.5 | `text-sm font-medium text-gray-900` |
+| Caption / metadata | 12px (text-xs) | 400 (normal) | 1.4 | `text-xs text-gray-400` |
+
+Weights in use: 400 (normal), 500 (medium), 600 (semibold), 700 (bold). No new weights added.
+
+Monospace (extracted text panel): `text-xs font-mono` at `text-gray-600` on `bg-gray-50` — established in DocumentView.vue, reuse for audit log detail cells.
+
+Section label / nav category: `text-xs font-semibold text-gray-400 uppercase tracking-wider` — established pattern, reuse for folder section header in sidebar.
+
+---
+
+## Color
+
+Source: AppSidebar.vue, QuotaBar.vue, DocumentCard.vue, DocumentView.vue. No new colors introduced.
+
+| Role | Tailwind value | Hex (approx) | Usage |
+|------|---------------|--------------|-------|
+| Dominant (60%) | `bg-white` | #ffffff | Page background, cards, sidebar background |
+| Secondary (30%) | `bg-gray-50` / `border-gray-200` | #f9fafb / #e5e7eb | Card hover surface, extracted text block background, modal backdrop inner panel, table row stripes |
+| Accent (10%) | `indigo-600` / `indigo-50` / `indigo-700` | #4f46e5 | Reserved-for list below |
+| Destructive | `red-600` / `red-700` | #dc2626 | Destructive action buttons only |
+| Warning — quota amber | `amber-500` / `amber-600` | #f59e0b | QuotaBar 80–95% (pre-existing, do not change) |
+| Warning — quota red | `red-500` / `red-600` | #ef4444 | QuotaBar ≥95% (pre-existing, do not change) |
+
+**Accent (indigo) reserved for:**
+- Active nav link background: `bg-indigo-50 text-indigo-700`
+- Primary action buttons (filled): `bg-indigo-600 hover:bg-indigo-700 text-white`
+- Document icon background: `bg-indigo-50` with `text-indigo-500` icon
+- Logo text: `text-indigo-600`
+- User avatar background: `bg-indigo-100 text-indigo-700`
+- QuotaBar fill (normal state): `bg-indigo-500`
+- Link text (back navigation, inline links): `text-indigo-600 hover:underline`
+- Checkbox / radio checked state: `text-indigo-600` (Tailwind form plugin default)
+- Share badge (shared indicator on document card): `bg-indigo-50 text-indigo-600` pill
+
+Accent is NOT used on: hover states of neutral UI, sort controls, breadcrumb separators, audit log rows, sidebar section labels, permission badges (use gray), or any informational text.
+
+**Shared indicator badge** (SHARE-05): small `bg-indigo-50 text-indigo-600 text-xs font-medium px-2 py-0.5 rounded-full` pill labeled "Shared" — shown inline in DocumentCard below the metadata line when `doc.share_count > 0`.
+
+**"Shared with me" virtual folder entry** (D-06): rendered with a distinct inbox-style icon (`bg-purple-50 text-purple-500`) to visually separate it from user-owned folders. Purple is used ONLY for this one sidebar entry to signal "received from others" vs. "my own". No other UI element uses purple.
+
+Folder row icons in main content: `bg-gray-100 text-gray-500` (neutral — folders are structural, not accent).
+
+---
+
+## Component Inventory
+
+New components required for Phase 4. All follow existing utility-class patterns.
+
+### FolderRow.vue
+- Used in HomeView main content area to render sub-folders within a folder.
+- Layout: `flex items-center gap-3 px-4 py-3 bg-white border border-gray-200 rounded-xl hover:border-indigo-300 hover:shadow-sm transition-all cursor-pointer`
+- Left: folder icon `w-9 h-9 rounded-lg bg-gray-100 flex items-center justify-center` with `text-gray-500` SVG folder icon (w-5 h-5).
+- Middle: folder name `font-medium text-gray-900 text-sm`, sub-label `text-xs text-gray-400` showing document count (e.g., "3 documents").
+- Right: three-dot menu button `text-gray-400 hover:text-gray-600` with dropdown for Rename and Delete actions.
+
+### FolderBreadcrumb.vue
+- Rendered above document list when inside a folder.
+- Segments: `flex items-center gap-2 text-sm`.
+- Each clickable segment: `text-indigo-600 hover:underline font-medium`.
+- Separator: SVG chevron-right `w-3 h-3 text-gray-400 shrink-0`.
+- Truncation rule (D-02): when depth > 4, show first segment + `…` button (plain text, `px-1 py-0.5 text-gray-400 hover:text-gray-600`) + last 2 segments.
+- Current (non-clickable) final segment: `text-gray-900 font-medium`.
+
+### ShareModal.vue
+- Triggered by share icon button on DocumentCard.
+- Modal overlay: `fixed inset-0 bg-black/40 flex items-center justify-center z-50`.
+- Panel: `bg-white rounded-2xl shadow-xl p-6 max-w-md w-full mx-4`.
+- Title: `text-lg font-semibold text-gray-900 mb-4` — "Share document".
+- Handle input row: `flex gap-2` — `<input type="text" placeholder="Enter username handle" class="flex-1 border border-gray-300 rounded-lg px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-indigo-500">` + primary button "Share" `bg-indigo-600 hover:bg-indigo-700 text-white text-sm px-4 py-2 rounded-lg`.
+- Separator: `border-t border-gray-100 my-4`.
+- Recipients list: each row `flex items-center justify-between py-2`.
+  - Left: handle `text-sm text-gray-900` + permission badge `text-xs bg-gray-100 text-gray-600 px-2 py-0.5 rounded-full font-medium ml-2` (shows "view").
+  - Right: "Revoke" `text-xs text-red-500 hover:text-red-700 font-medium` button.
+- Empty state: `text-sm text-gray-400 italic py-2` — "Not shared with anyone yet."
+- Close button: top-right `absolute top-4 right-4`, `text-gray-400 hover:text-gray-600`, SVG X icon w-5 h-5.
+
+### FolderDeleteModal.vue
+- Triggered when deleting a non-empty folder (D-03).
+- Reuses ConfirmBlock.vue pattern but rendered in a modal panel (same overlay style as ShareModal).
+- Warning icon: `w-10 h-10 bg-red-50 rounded-full flex items-center justify-center` with `text-red-500` exclamation SVG, centered at top of modal.
+- Heading: `text-lg font-semibold text-gray-900 mt-4 text-center` — "Delete folder?"
+- Body: `text-sm text-gray-600 text-center mt-2 mb-6` — "This folder contains {N} documents. Deleting it will permanently delete all documents inside. This cannot be undone."
+- Buttons: `flex gap-3 justify-end`. Cancel: `text-sm text-gray-600 hover:text-gray-800 px-4 py-2`. Confirm: `bg-red-600 hover:bg-red-700 text-white text-sm font-semibold px-4 py-2 rounded-lg min-h-[44px]` — "Delete folder and documents".
+
+### DocumentPreviewModal.vue (in-app mode only)
+- Used when `user.pdf_open_mode === 'in_app'` (D-10).
+- Overlay: `fixed inset-0 bg-black/60 z-50 flex flex-col`.
+- Header bar: `bg-white border-b border-gray-200 px-6 py-3 flex items-center justify-between`.
+  - Left: document name `text-sm font-medium text-gray-900 truncate max-w-xs`.
+  - Right: close button `text-gray-400 hover:text-gray-600`, SVG X w-5 h-5.
+- Content: `flex-1 overflow-hidden` — `<iframe class="w-full h-full border-0" :src="proxyUrl" title="Document preview">`.
+- No loading spinner needed — browser handles iframe load state.
+
+### SearchBar.vue (inline in HomeView/FolderView)
+- Rendered above the document list, right-aligned alongside sort controls.
+- `<input type="search" placeholder="Search documents…" class="border border-gray-300 rounded-lg px-3 py-2 text-sm w-56 focus:outline-none focus:ring-2 focus:ring-indigo-500 focus:border-transparent">`.
+- Debounced 300 ms. Minimum 2 characters before firing. Clears on Escape key.
+- While searching (debounce pending): no spinner — results just update.
+- No results: inline empty state text below the list area (see copywriting below).
+
+### SortControls.vue (inline in HomeView/FolderView)
+- Three text buttons: "Name" / "Date" / "Size" — `text-xs text-gray-500 hover:text-gray-900 font-medium px-2 py-1 rounded`.
+- Active sort: `text-indigo-600 font-semibold`. Direction indicator: `↑` or `↓` suffix appended to active label.
+
+### AuditLogTab.vue (extends AdminView)
+- New tab added to AdminView alongside existing Users, Quotas, AI Config tabs.
+- Filter bar: `flex flex-wrap gap-3 mb-4 items-end`.
+  - Date range: two `<input type="date">` fields with `text-sm border border-gray-300 rounded-lg px-3 py-2 focus:ring-indigo-500`.
+  - User dropdown: `<select>` with same styling — "All users" default.
+  - Action type dropdown: same styling — "All actions" default.
+  - Apply button: `bg-indigo-600 text-white text-sm px-4 py-2 rounded-lg hover:bg-indigo-700`.
+  - Export button: `border border-gray-300 text-gray-700 text-sm px-4 py-2 rounded-lg hover:bg-gray-50` — "Export CSV".
+- Table: `w-full text-sm border-collapse`.
+  - Header row: `text-xs font-semibold text-gray-400 uppercase tracking-wider` on `bg-gray-50 border-b border-gray-200`.
+  - Columns: Timestamp | User | Action Type | IP Address.
+  - Body row: `border-b border-gray-100 hover:bg-gray-50`. Cells: `px-4 py-3 text-sm text-gray-700`.
+  - Timestamp: monospace `font-mono text-xs text-gray-500`.
+  - Action type: pill badge `text-xs px-2 py-0.5 rounded-full font-medium` — color-coded by category: auth=`bg-blue-50 text-blue-600`, document=`bg-gray-100 text-gray-600`, folder/share=`bg-purple-50 text-purple-600`, admin=`bg-amber-50 text-amber-700`.
+- Pagination: `flex items-center justify-between mt-4`. "Previous" / "Next" text buttons. Page indicator `text-sm text-gray-500`.
+- Empty state: centered `py-12 text-gray-400 text-sm` — "No audit log entries match the selected filters."
+
+---
+
+## AppSidebar Extensions
+
+Extend AppSidebar.vue with new sections (D-01, D-06). Order top to bottom:
+
+1. Logo section (unchanged)
+2. Nav links: Home, All Topics (unchanged)
+3. **NEW — "Shared with me" entry** (fixed, above folders): rendered with inbox icon `bg-purple-50 text-purple-500`. If `sharedCount > 0`, show count badge `ml-auto bg-purple-100 text-purple-600 text-xs font-semibold rounded-full px-1.5 min-w-[18px] text-center`. Route: `/shared`.
+4. **NEW — Folders section**: section label `text-xs font-semibold text-gray-400 uppercase tracking-wider mb-1` — "Folders". "New folder" inline button: `text-xs text-indigo-600 hover:underline` — appears to the right of the section label. Each top-level folder: `nav-link` style (same as topic links) with folder SVG icon `w-4 h-4 mr-2` and truncated name. Active when `$route.params.folderId === folder.id`.
+5. Topics list (unchanged)
+6. QuotaBar (unchanged)
+7. Settings + Admin footer (unchanged)
+
+---
+
+## DocumentCard Extensions
+
+Extend DocumentCard.vue with two additions (D-05, SHARE-05):
+
+1. **Share button**: icon-only button, appears on card hover (`opacity-0 group-hover:opacity-100 transition-opacity`). Add `group` class to outer div. Button: `p-1.5 rounded-md text-gray-400 hover:text-indigo-600 hover:bg-indigo-50 transition-colors min-h-[44px] min-w-[44px] flex items-center justify-center` — share/export SVG icon w-4 h-4. Position: absolute top-right within the card header row, alongside a potential future menu.
+2. **Shared indicator pill** (SHARE-05): `bg-indigo-50 text-indigo-600 text-xs font-medium px-2 py-0.5 rounded-full` — "Shared" — shown inline below the metadata line when `doc.share_count > 0`.
+
+---
+
+## Copywriting Contract
+
+Source: 04-CONTEXT.md `<specifics>` block + requirement descriptions.
+
+### Folders
+
+| Element | Copy |
+|---------|------|
+| New folder CTA | "New folder" |
+| Folder rename action | "Rename" |
+| Folder delete action | "Delete folder" |
+| Empty folder state (no documents, no sub-folders) | "This folder is empty." / "Upload documents or create sub-folders to organize your files." |
+| Non-empty folder delete heading | "Delete folder?" |
+| Non-empty folder delete body | "This folder contains {N} document{s}. Deleting it will permanently delete all documents inside. This cannot be undone." |
+| Non-empty folder delete confirm button | "Delete folder and documents" |
+| Non-empty folder delete cancel button | "Cancel" |
+| Move document action | "Move to folder" |
+| Move document success (no toast — inline list refresh only) | n/a |
+
+### Sharing
+
+| Element | Copy |
+|---------|------|
+| Share button aria-label | "Share document" |
+| Share modal title | "Share document" |
+| Handle input placeholder | "Enter username handle" |
+| Share submit CTA | "Share" |
+| User not found error (D-04) | "User not found. Check the handle and try again." |
+| Already shared error | "This document is already shared with that user." |
+| Share success (no toast — list refreshes inline) | n/a |
+| Revoke action label | "Revoke" |
+| Revoke confirm (inline, no modal) | None — single click revokes immediately (low-stakes, immediately visible in list) |
+| Empty recipients state | "Not shared with anyone yet." |
+| "Shared with me" sidebar label | "Shared with me" |
+| "Shared with me" empty state heading | "No documents shared with you yet." |
+| "Shared with me" empty state body | "When someone shares a document with you, it will appear here." |
+
+### Document List & Search
+
+| Element | Copy |
+|---------|------|
+| Search placeholder | "Search documents…" |
+| No results state (after search) | "No documents match "{query}"." / "Try a different search term." |
+| Document list empty state (no documents, no search) | "No documents yet. Upload one above." (pre-existing, unchanged) |
+| Sort label prefix | "Sort by:" — rendered as accessible visually-hidden label; buttons labeled "Name", "Date", "Size" |
+
+### PDF Preview
+
+| Element | Copy |
+|---------|------|
+| Document preferences section heading | "Document Preferences" |
+| PDF open mode radio option 1 | "Open documents in-app" |
+| PDF open mode radio option 2 | "Open documents in new tab" |
+| Preview close button aria-label | "Close preview" |
+
+### Audit Log
+
+| Element | Copy |
+|---------|------|
+| Audit log tab label | "Audit Log" |
+| Filter apply CTA | "Apply filters" |
+| Export CTA | "Export CSV" |
+| Empty state (no results) | "No audit log entries match the selected filters." |
+| Date range label | "From" / "To" |
+| User filter label | "User" with default option "All users" |
+| Action type filter label | "Action" with default option "All actions" |
+| Pagination previous | "Previous" |
+| Pagination next | "Next" |
+
+### Error States (general)
+
+| Element | Copy |
+|---------|------|
+| Generic API failure | "Something went wrong. Please try again." |
+| Network error | "Unable to connect. Check your connection and try again." |
+| 404 (folder or document not found) | "This {folder/document} no longer exists." |
+| Quota rejection on upload (pre-existing, do not change) | As implemented in Phase 3 UploadProgress.vue |
+
+---
+
+## Interaction Contracts
+
+### Folder Navigation
+- Clicking a top-level folder in the sidebar navigates to `/folders/{id}`.
+- Within a folder view, sub-folder rows are rendered above document cards.
+- Clicking a sub-folder row navigates deeper: `/folders/{id}`.
+- Breadcrumb segments are anchor/router-link elements — keyboard navigable.
+- "New folder" triggers an inline text field directly in the folder list (not a modal), pre-focused, Escape cancels, Enter submits, empty name submits are rejected client-side with `text-red-500 text-xs mt-1` error inline.
+
+### Folder Rename
+- Three-dot menu on FolderRow opens a `position: absolute` dropdown `bg-white border border-gray-200 rounded-lg shadow-md py-1 min-w-[120px] z-10` with two items: "Rename" and "Delete folder". Menu closes on outside click.
+- Rename: replaces folder name text with an inline `<input>` pre-filled with current name. Same commit behavior as new folder (Enter = save, Escape = cancel).
+
+### Document Sort
+- Default sort: Date, descending (newest first).
+- Sort state lives in local view state (not URL params) for Phase 4 MVP.
+- Sort change triggers immediate re-fetch with `?sort=name|date|size&order=asc|desc` query params.
+
+### Search Debounce
+- 300 ms debounce. Fires only when input length >= 2.
+- While a search request is in-flight, a `text-gray-400 text-xs` "Searching…" message appears inline below the search bar (not a spinner).
+- Clearing the search input (empty string) immediately restores the full document list without an API call.
+
+### Share Modal
+- Share modal does not close after a successful share — the handle input clears and the recipient list updates inline, allowing additional shares without reopening.
+- "Revoke" removes the row immediately (optimistic UI — if API fails, row re-appears with `text-red-500 text-xs` error appended to it).
+
+### PDF Preview (in-app mode)
+- Clicking a PDF document card opens DocumentPreviewModal.vue if `pdf_open_mode === 'in_app'`.
+- Non-PDF documents continue to navigate to DocumentView (metadata/extracted text).
+- PDFs also show metadata/extracted text in DocumentView when accessed via direct URL (modal is a shortcut, not the only path).
+- Clicking outside the modal panel (on the overlay) closes the modal.
+- Pressing Escape closes the modal.
+
+### Audit Log Pagination
+- Page size: 50 rows per page.
+- Pagination via `?page=N&page_size=50` query params on the audit log API endpoint.
+- Filter changes reset to page 1.
+
+---
+
+## Accessibility Contracts
+
+- All icon-only buttons (share, close, three-dot menu, revoke) have `aria-label` attributes.
+- Modal overlays set `role="dialog" aria-modal="true" aria-labelledby="{modal-title-id}"`.
+- Modal opening focuses the first interactive element inside the panel.
+- Modal closing returns focus to the trigger element.
+- Sort buttons set `aria-pressed="true"` on the active sort. Direction change is conveyed via visible `↑`/`↓` character plus `aria-label` including direction (e.g., `aria-label="Sort by name, ascending"`).
+- Breadcrumb wrapper: `<nav aria-label="Folder navigation">` with `<ol>` list structure.
+- Search input: `role="search"` on the wrapping `<div>`, `aria-label="Search documents"` on the input.
+- QuotaBar: `role="progressbar"` already implemented — no change.
+- Audit log table: `<table>` with `<thead>`, `<th scope="col">` headers.
+- FolderDeleteModal, ShareModal: trap focus within modal while open.
+
+---
+
+## Registry Safety
+
+| Registry | Blocks Used | Safety Gate |
+|----------|-------------|-------------|
+| shadcn official | none | not applicable — no shadcn in this project |
+| Third-party | none | not applicable |
+
+No third-party component registries. All new components are hand-authored Tailwind utility classes following established project patterns. No new npm packages for UI components.
+
+---
+
+## New Files Required
+
+| File | Purpose |
+|------|---------|
+| `frontend/src/components/folders/FolderRow.vue` | Folder row in main content area |
+| `frontend/src/components/folders/FolderBreadcrumb.vue` | Breadcrumb navigation |
+| `frontend/src/components/folders/FolderDeleteModal.vue` | Non-empty folder delete confirmation |
+| `frontend/src/components/sharing/ShareModal.vue` | Share by handle + revoke list |
+| `frontend/src/components/documents/DocumentPreviewModal.vue` | In-app PDF preview via iframe |
+| `frontend/src/components/documents/SearchBar.vue` | Debounced full-text search input |
+| `frontend/src/components/documents/SortControls.vue` | Name / Date / Size sort toggle |
+| `frontend/src/components/admin/AuditLogTab.vue` | Admin audit log viewer with filters + export |
+| `frontend/src/views/FolderView.vue` | Folder contents view (sub-folders + documents + breadcrumb) |
+| `frontend/src/views/SharedView.vue` | "Shared with me" virtual folder view |
+
+Existing files extended (not replaced):
+- `frontend/src/components/layout/AppSidebar.vue` — add Shared with me entry + Folders section
+- `frontend/src/components/documents/DocumentCard.vue` — add share button + shared indicator pill
+- `frontend/src/views/HomeView.vue` — add SearchBar + SortControls above document list
+- `frontend/src/views/DocumentView.vue` — add PDF preview trigger logic
+- `frontend/src/views/AdminView.vue` — add AuditLog tab
+- `frontend/src/views/SettingsView.vue` — add Document Preferences card with pdf_open_mode radio
+
+---
+
+## Checker Sign-Off
+
+- [ ] Dimension 1 Copywriting: PASS
+- [ ] Dimension 2 Visuals: PASS
+- [ ] Dimension 3 Color: PASS
+- [ ] Dimension 4 Typography: PASS
+- [ ] Dimension 5 Spacing: PASS
+- [ ] Dimension 6 Registry Safety: PASS
+
+**Approval:** pending