Add empty-state designs for empty playlists and history

Replaces bare status text with visual empty-state components:
- History: clock icon, 'Nothing watched yet' title, description, 'Search videos' CTA
- Playlist: music icon, 'This playlist is empty' title, description with tip, 'Browse videos' CTA
- Search: unchanged (hero landing handles this case)
- CTA buttons navigate to search view for quick action

BACKLOG.md

@@ -0,0 +1,39 @@
+# YT Player — Improvement Backlog
+
+The `/loop` works through this top-to-bottom, **one item per iteration**. Tick an item
+(`[x]`) only after it builds, verifies, and is committed + pushed. Add new ideas to the
+bottom as they come up.
+
+## Build & verify protocol (every iteration)
+1. Edit the **canonical source** in WSL (`~/development/personal/ytplayer`).
+2. Sync changed files **individually** into `C:\ytbuild\ytplayer` — never
+   `Copy-Item -Recurse` onto an existing dir (it nests as `frontend\frontend`).
+3. `npx tauri build` in `C:\ytbuild\ytplayer`.
+4. Launch with `--remote-debugging-port=922x` and verify via CDP/screenshot
+   (retry the launch a few times — Smart App Control is intermittent).
+5. **Only if it builds and verifies:** refresh `releases/`, commit (no AI attribution),
+   `git push origin main`, then tick the item here.
+
+## UX / polish
+- [x] Empty-state designs for empty playlists and empty history (match the new hero).
+- [ ] Loading skeletons for search results instead of a bare "Searching…".
+- [ ] Keyboard-shortcut help overlay (press `?`), listing space / arrows / f / m.
+- [ ] Download/preload progress indicator on cards (percent or a bar, not just a pulse).
+- [ ] Remember and restore the last playback position per video.
+- [ ] Toast queue (stack multiple toasts instead of replacing).
+
+## Features
+- [ ] Drag-to-reorder videos within a playlist.
+- [ ] "Up next" queue panel showing the autoplay queue.
+- [ ] Persistent mini now-playing bar when browsing other views.
+- [ ] Cache size cap in Settings (auto-evict oldest past a limit).
+- [ ] Export / import playlists as JSON.
+- [ ] More / trending quick-search chips on the hero, rotated.
+
+## Robustness
+- [ ] Sanitize `video_id` in `cache_download` (reject path separators).
+- [ ] Gate the embedded yt-dlp behind a build flag so debug builds compile faster.
+- [ ] Surface yt-dlp extraction failures with a retry button.
+
+## Done
+<!-- move completed items here with the commit hash -->

frontend/app.js

@@ -596,11 +596,44 @@ function renderList() {
   }
 
   if (!list.length) {
-    els.status.classList.remove('hidden');
-    els.status.textContent =
-      view.type === 'search' ? 'Search for something to begin.'
-      : view.type === 'history' ? 'Nothing watched yet.'
-      : 'This playlist is empty. Add videos from search.';
+    els.status.classList.add('hidden');
+    els.cards.innerHTML = '';
+    const empty = document.createElement('div');
+    empty.className = 'empty-state';
+
+    if (view.type === 'search') {
+      // Hero landing is already in the player pane — list pane stays bare.
+      els.status.classList.remove('hidden');
+      els.status.textContent = 'Search for something to begin.';
+      return;
+    }
+
+    if (view.type === 'history') {
+      empty.innerHTML = `
+        <div class="empty-icon">🕘</div>
+        <h3 class="empty-title">Nothing watched yet</h3>
+        <p class="empty-desc">Your viewing history shows up here once you start playing videos.</p>
+      `;
+      const cta = document.createElement('button');
+      cta.className = 'empty-cta';
+      cta.textContent = '🔍  Search videos';
+      cta.addEventListener('click', () => { view = { type: 'search' }; render(); });
+      empty.appendChild(cta);
+    } else {
+      // Playlist view — empty
+      empty.innerHTML = `
+        <div class="empty-icon">🎵</div>
+        <h3 class="empty-title">This playlist is empty</h3>
+        <p class="empty-desc">Add videos from search results or use the <strong>+ Playlist</strong> button while playing.</p>
+      `;
+      const cta = document.createElement('button');
+      cta.className = 'empty-cta';
+      cta.textContent = '🔍  Browse videos';
+      cta.addEventListener('click', () => { view = { type: 'search' }; render(); });
+      empty.appendChild(cta);
+    }
+
+    els.cards.appendChild(empty);
     return;
   }
   els.status.classList.add('hidden');

frontend/styles.css

@@ -557,6 +557,66 @@ input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.25); }
 .list-actions button:hover { color: var(--text); border-color: var(--accent); background: var(--bg-3); }
 
 .status { padding: 16px 20px; color: var(--text-dim); font-size: 13px; }
+
+/* ===================== Empty state ===================== */
+.empty-state {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  text-align: center;
+  padding: 40px 32px 60px;
+  gap: 8px;
+  animation: heroIn 0.5s var(--ease) both;
+}
+.empty-icon {
+  font-size: 42px;
+  width: 80px; height: 80px;
+  display: grid; place-items: center;
+  border-radius: 24px;
+  background: var(--bg-2);
+  border: 1px solid var(--line);
+  margin-bottom: 10px;
+  transition: transform 0.3s var(--ease), box-shadow 0.3s;
+}
+.empty-state:hover .empty-icon {
+  transform: translateY(-4px);
+  box-shadow: 0 12px 32px -12px var(--accent-glow);
+}
+.empty-title {
+  font-family: var(--display);
+  font-weight: 700;
+  font-size: 18px;
+  letter-spacing: -0.01em;
+  margin: 0;
+  color: var(--text);
+}
+.empty-desc {
+  margin: 4px 0 0;
+  color: var(--text-dim);
+  font-size: 13.5px;
+  line-height: 1.5;
+  max-width: 300px;
+}
+.empty-desc strong { color: var(--text-2); font-weight: 600; }
+.empty-cta {
+  margin-top: 16px;
+  background: linear-gradient(145deg, var(--accent-bright), var(--accent-deep));
+  color: #fff;
+  border: none;
+  padding: 10px 22px;
+  border-radius: 11px;
+  font-family: var(--ui);
+  font-weight: 700;
+  font-size: 13px;
+  letter-spacing: 0.01em;
+  cursor: pointer;
+  box-shadow: 0 8px 22px -8px var(--accent-glow);
+  transition: transform 0.16s var(--ease), box-shadow 0.16s;
+}
+.empty-cta:hover { transform: translateY(-2px); box-shadow: 0 12px 28px -8px var(--accent-glow); }
+.empty-cta:active { transform: translateY(0); }
+
 .cards { flex: 1; overflow-y: auto; padding: 6px 14px 28px; display: flex; flex-direction: column; gap: 5px; }
 
 .card {