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+# TutorialVault — 15 UI Enhancements Design
+
+**Goal:** Add 15 real, polished enhancements to the TutorialVault frontend — all WCAG 2.2 AAA compliant.
+
+**Architecture:** All changes are frontend-only (TypeScript + CSS). No Rust/backend changes needed. Each enhancement is independent — no cross-dependencies between them.
+
+**Tech Stack:** TypeScript, CSS, HTML (Tauri v2 webview frontend)
+
+---
+
+## Enhancement 1: Mute Toggle (M key + volume icon click)
+
+**What:** Press `M` to toggle mute. Click the volume icon to toggle mute. Muted state shows `fa-volume-xmark`, grays out the slider. Unmuting restores previous volume.
+
+**Files:** `main.ts`, `player.ts`, `player.css`
+
+**Behavior:**
+- Store `lastVolume` before muting. Set volume to 0 on mute.
+- On unmute, restore `lastVolume` (default 1.0 if none stored).
+- Volume icon dynamically swaps: `fa-volume-high` (>50%), `fa-volume-low` (>0%), `fa-volume-xmark` (0/muted).
+- Dragging the volume slider while muted unmutes automatically.
+
+**WCAG:** Volume icon gets `aria-label="Mute"/"Unmute"` dynamically. Muted visual uses icon change + reduced opacity (not color alone).
+
+---
+
+## Enhancement 2: Fullscreen Shortcut (F key)
+
+**What:** Press `F` to toggle fullscreen. Mirrors the existing fullscreen button behavior.
+
+**Files:** `main.ts`
+
+**Behavior:** Add `case 'f':` to the keyboard switch. Calls the same fullscreen toggle as `fsBtn.onclick`.
+
+**WCAG:** No visual changes needed.
+
+---
+
+## Enhancement 3: Seek Feedback Overlay
+
+**What:** Flash `−5s` / `+5s` text in the video overlay when seeking via arrow keys. Fades after 600ms.
+
+**Files:** `main.ts`, `player.ts`, `player.css`
+
+**Behavior:**
+- New `showSeekFeedback(delta: number)` function in player.ts.
+- Reuses the existing video overlay area. Shows text like "−5s" or "+5s" centered.
+- Uses a CSS class `.seekFeedback` that fades in/out.
+- Consecutive presses accumulate: pressing ArrowRight 3 times quickly shows "+15s".
+
+**WCAG:** Overlay area has `aria-live="assertive"` so screen readers announce "Seeked forward 5 seconds". Text meets 7:1 contrast (white on semi-transparent dark).
+
+---
+
+## Enhancement 4: Playlist Search/Filter
+
+**What:** Search input above the playlist. Typing filters by video name or relative path in real-time. Shows "X of Y" while filtering. Clear button (x) resets.
+
+**Files:** `index.html`, `playlist.ts`, `playlist.css`
+
+**Behavior:**
+- Add `<input id="plistSearch">` in the playlist `.panelHeader`.
+- `renderList()` checks the filter value and skips non-matching items.
+- Filter is case-insensitive, matches against `it.title`, `it.name`, `it.relpath`.
+- Clear button appears only when input has text.
+- Pressing Escape in the search input clears it.
+
+**WCAG:** `aria-label="Search playlist"`. Filtered count via `aria-live="polite"` region. Clear button has 44x44 target and `aria-label="Clear search"`.
+
+---
+
+## Enhancement 5: Scroll-to-Current Button
+
+**What:** Button in playlist header that scrolls the active item into view. Only visible when the active item is off-screen.
+
+**Files:** `index.html`, `playlist.ts`, `playlist.css`
+
+**Behavior:**
+- Uses `IntersectionObserver` on the `.row.active` element.
+- Button appears (fades in) when active row is not visible.
+- Clicking calls `activeRow.scrollIntoView({ block: 'center', behavior: 'smooth' })`.
+- Icon: `fa-crosshairs` or `fa-location-dot`.
+
+**WCAG:** `aria-label="Scroll to current video"`. 44x44 touch target. Hidden with `display:none` when not actionable (removed from a11y tree).
+
+---
+
+## Enhancement 6: Picture-in-Picture Button
+
+**What:** PiP toggle button next to the fullscreen button. Uses native `requestPictureInPicture()` API.
+
+**Files:** `index.html`, `player.ts`
+
+**Behavior:**
+- New `iconBtn` after fsBtn: `<button class="iconBtn" id="pipBtn">`.
+- Icon swaps: `fa-up-right-from-square` (enter PiP) / `fa-down-left-and-up-right-to-center` (exit PiP).
+- Listen to `enterpictureinpicture` / `leavepictureinpicture` events to update icon.
+- Feature-detect: hide button if `document.pictureInPictureEnabled` is false.
+
+**WCAG:** Dynamic `aria-label="Enter picture-in-picture"/"Exit picture-in-picture"`. Same focus-visible ring as all icon buttons.
+
+---
+
+## Enhancement 7: Timestamp Insertion in Notes
+
+**What:** Button in the notes dock header that inserts `[MM:SS] ` at the textarea cursor position using the current video time.
+
+**Files:** `index.html`, `ui.ts`, `panels.css`
+
+**Behavior:**
+- Small button in `#notesHeader`: `<button id="insertTimestamp" aria-label="Insert timestamp">`.
+- Icon: `fa-clock` or `fa-stopwatch`.
+- On click: read `player.currentTime`, format as `[M:SS]`, insert at `notesBox.selectionStart`.
+- After insert, focus the textarea and place cursor after the inserted text.
+
+**WCAG:** `aria-label="Insert timestamp"`. 44x44 target via `::before` expansion. `data-tooltip` for hover discoverability.
+
+---
+
+## Enhancement 8: Keyboard Shortcut Help Panel
+
+**What:** Press `?` to open a help overlay listing all keyboard shortcuts. Press `?` or `Escape` to close.
+
+**Files:** `index.html`, `main.ts`, `main.css` or `components.css`
+
+**Behavior:**
+- Hidden `<div id="shortcutHelp" role="dialog" aria-label="Keyboard shortcuts">` in HTML.
+- Two-column grid showing key + description pairs.
+- Shortcuts shown: Space (play/pause), Left/Right (seek ±5s), Up/Down (volume), M (mute), F (fullscreen), [ / ] (speed), Alt+Arrow (reorder playlist), ? (this help).
+- Focus trap inside the dialog while open.
+- Semi-transparent dark backdrop.
+
+**WCAG:** `role="dialog"` with `aria-label`. Focus trapped. Escape closes. All text 7:1 contrast. Backdrop doesn't remove background content from a11y tree (uses `aria-hidden="true"` on app root while dialog is open).
+
+---
+
+## Enhancement 9: Playback Speed Shortcuts ([ and ])
+
+**What:** Press `[` to decrease speed one step, `]` to increase speed one step through the SPEEDS array.
+
+**Files:** `main.ts`, `player.ts`
+
+**Behavior:**
+- New `cycleSpeed(delta: number)` exported from player.ts.
+- Finds current speed in SPEEDS array, moves by delta (clamped to bounds).
+- Updates speed button text, gauge icon, and saves to backend.
+- Shows toast notification: "Speed: 1.25x".
+
+**WCAG:** Speed change announced via toast (existing `aria-live="polite"` region).
+
+---
+
+## Enhancement 10: Reset Progress Confirmation
+
+**What:** Two-click confirmation before resetting progress. First click changes button to "Confirm?" state with red tint. Second click within 3 seconds actually resets. Timeout or click-away cancels.
+
+**Files:** `ui.ts`, `main.css`
+
+**Behavior:**
+- First click: add `.confirming` class, change icon to `fa-exclamation-triangle`, start 3s timer.
+- Second click while `.confirming`: execute the actual reset.
+- Timer expiry or blur: remove `.confirming`, restore original icon.
+- `.confirming` state: red-tinted background (`rgba(255,70,70,.14)`).
+
+**WCAG:** `aria-label` changes to "Confirm reset progress" in confirm state. Visual change uses both color AND icon change (not color alone).
+
+---
+
+## Enhancement 11: Video Load Error State
+
+**What:** When the `<video>` fires an error event, show a centered overlay with warning icon, error message, and "Try next" button.
+
+**Files:** `player.ts`, `player.css`
+
+**Behavior:**
+- Listen to `player.addEventListener('error', ...)`.
+- Create/show error overlay inside `.videoWrap` with `fa-triangle-exclamation` icon.
+- Message: "This file format may not be supported. Try MP4 (H.264/AAC) or WebM."
+- "Try next" button calls `nextPrev(+1)`.
+- Overlay clears on next successful `loadedmetadata`.
+
+**WCAG:** `role="alert"` for screen reader announcement. "Try next" button has 44x44 target. Error text meets 7:1 contrast.
+
+---
+
+## Enhancement 12: Double-Click to Fullscreen
+
+**What:** Double-clicking the video toggles fullscreen. Single click still toggles play/pause.
+
+**Files:** `player.ts`
+
+**Behavior:**
+- Replace simple click handler with a click/double-click discriminator.
+- On click: set a 300ms timer. If no second click arrives, toggle play/pause.
+- On double-click: cancel the timer, toggle fullscreen instead.
+- `dblclick` event on the video overlay area.
+
+**WCAG:** Mouse/touch enhancement only. Fullscreen remains keyboard-accessible via F key and button.
+
+---
+
+## Enhancement 13: Playlist Stats in Header
+
+**What:** Show video count and completion info next to "Playlist" header. E.g., "24 videos  ·  8 done".
+
+**Files:** `index.html`, `playlist.ts`
+
+**Behavior:**
+- Add `<span class="plistStats" id="plistStats"></span>` in the panelHeader.
+- In `renderList()`: compute total count, done count, update the span.
+- Styled as `--textMuted`, smaller font (11px), monospace.
+
+**WCAG:** Stats text meets 7:1 contrast. Updated via DOM so screen readers can read it on demand.
+
+---
+
+## Enhancement 14: Mini Progress Bars Per Playlist Item
+
+**What:** Thin 2px progress bar at the bottom of each playlist row showing watched/total. Green for done, accent blue for in-progress.
+
+**Files:** `playlist.ts`, `playlist.css`
+
+**Behavior:**
+- For each row in `renderList()`, create a `.rowProgress` div.
+- Width: `(watched / duration) * 100%`. If duration is null, hide.
+- Color: `--success` for done items, `--accent` for in-progress.
+- Positioned absolutely at bottom of the row.
+
+**WCAG:** `aria-hidden="true"` — numeric info already in the row's `aria-label`. Colors pass 3:1 minimum for non-text contrast per WCAG 2.2.
+
+---
+
+## Enhancement 15: Collapsible Dock Panes
+
+**What:** Clicking a dock header collapses that pane, giving the other pane full height. Collapsed state shows just the header with a chevron. Persisted via prefs.
+
+**Files:** `ui.ts`, `panels.css`, `index.html`
+
+**Behavior:**
+- Click on `.dockHeader` toggles `.collapsed` on the parent `.dockPane`.
+- Collapsed: `flex:0 0 auto`, content inside has `display:none`.
+- Chevron icon in header rotates to indicate collapsed/expanded.
+- Collapsing one pane doesn't collapse the other.
+- State saved in prefs as `notes_collapsed` / `info_collapsed` booleans.
+
+**WCAG:** Headers get `aria-expanded="true"/"false"`. Chevron is `aria-hidden="true"`. Enter/Space on header toggles. Collapsed content is `display:none` (removed from a11y tree).
+
+---
+
+## Approach
+
+**Single-pass, all frontend:** Every enhancement modifies only TypeScript and CSS files. No backend/Rust changes. Each enhancement is independent and can be implemented in any order.
+
+**Implementation strategy:** Direct edits to existing files using Edit/Write tools. No subagents for file editing. Each enhancement touches 1-3 files. Build verification after each enhancement or batch.
+
+**Testing:** `npm run build` (TypeScript compilation + Vite build) after each enhancement to catch errors immediately.