From e2cd8f50a3d34fafc19182591b4436b8156bf2f1 Mon Sep 17 00:00:00 2001
From: Ali Orhun Akkirman <aoakkirman@gmail.com>
Date: Mon, 28 Sep 2026 15:33:39 +0300
Subject: [PATCH] Add notebook management and global search

---
 README.md                  |  12 +-
 index.html                 | 184 ++++++++++++++-
 scripts/verify-offline.mjs |  16 ++
 src/app.js                 | 442 ++++++++++++++++++++++++++++++++++++-
 4 files changed, 644 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index 2306c40..d195070 100644
--- a/README.md
+++ b/README.md
@@ -77,8 +77,17 @@ Sağ üstteki **Export** düğmesiyle mevcut sekme içeriği şu biçimlerde dı
 
 ### Çoklu Sekme
 - `+` düğmesiyle yeni dosya/sekme oluşturma
+- Sekme adına çift tıklayarak veya sağ tık menüsünden yeniden adlandırma
+- Sağ tık menüsünden notebook kopyalama
+- Sekmeleri sürükle-bırak ile yeniden sıralama
+- Kapatılan notebook'u 8 saniye içinde **Geri Al** ile geri getirme
 - Sekmeler `localStorage`'da kalıcı olarak saklanır
-- Sekme adı çift tıkla düzenlenebilir
+
+### Notebook Arama
+- Üst bardaki **Ara / Search** düğmesi veya `Ctrl/Cmd + K` ile tüm notebook'larda arama
+- Dosya adı ve satır içeriği birlikte aranır
+- Sonuçlarda notebook adı, satır numarası ve içerik önizlemesi gösterilir
+- Sonuca tıklanınca ilgili notebook açılır ve eşleşen satıra odaklanılır
 
 ### Ekle Modalı
 `+` FAB (sağ alt) veya klavye kısayoluyla açılır. Şablonlu form üzerinden şunlar eklenebilir:
@@ -132,6 +141,7 @@ Bu kontrol, build çıktısında uzak script/style/module bağlantısı kalmadı
 |---------|-------|
 | `Ctrl` + `+` | Yakınlaştır |
 | `Ctrl` + `-` | Uzaklaştır |
+| `Ctrl/Cmd` + `K` | Tüm notebook'larda ara |
 
 ---
 
diff --git a/index.html b/index.html
index 7b9f382..f3fa652 100644
--- a/index.html
+++ b/index.html
@@ -66,7 +66,7 @@
   border-radius: 6px;
   padding: 2px;
 }
-#export-btn, #backup-btn, #examples-btn, #info-btn {
+#export-btn, #backup-btn, #examples-btn, #search-btn, #info-btn {
   padding: 4px 10px;
   border: 1px solid #ced4da;
   background: #fff;
@@ -82,7 +82,7 @@
   gap: 4px;
   white-space: nowrap;
 }
-#export-btn:hover, #backup-btn:hover, #examples-btn:hover, #info-btn:hover {
+#export-btn:hover, #backup-btn:hover, #examples-btn:hover, #search-btn:hover, #info-btn:hover {
   background: #f1f3f5;
   border-color: #1A71C2;
   color: #1A71C2;
@@ -268,6 +268,77 @@
 }
 #new-tab-btn:hover { background: #f1f3f5; color: #495057; }
 
+.file-tab.dragging {
+  opacity: 0.45;
+}
+.file-tab.drag-over {
+  border-left: 3px solid #1971c2;
+  padding-left: 11px;
+}
+.tab-context-menu {
+  position: fixed;
+  min-width: 170px;
+  padding: 5px;
+  border: 1px solid #dee2e6;
+  border-radius: 7px;
+  background: #fff;
+  box-shadow: 0 10px 28px rgba(0,0,0,0.14);
+  z-index: 1600;
+  display: none;
+}
+.tab-context-menu.active { display: block; }
+.tab-context-menu button {
+  width: 100%;
+  display: block;
+  padding: 7px 9px;
+  border: 0;
+  border-radius: 5px;
+  background: transparent;
+  color: #343a40;
+  text-align: left;
+  cursor: pointer;
+  font: inherit;
+  font-size: 12px;
+}
+.tab-context-menu button:hover {
+  background: #f1f3f5;
+  color: #1971c2;
+}
+.undo-toast {
+  position: fixed;
+  left: 50%;
+  bottom: 42px;
+  transform: translate(-50%, 12px);
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  max-width: min(520px, calc(100vw - 28px));
+  padding: 9px 12px;
+  border-radius: 8px;
+  background: #343a40;
+  color: #fff;
+  box-shadow: 0 8px 24px rgba(0,0,0,0.2);
+  z-index: 1700;
+  font-size: 12px;
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity .16s ease, transform .16s ease;
+}
+.undo-toast.active {
+  opacity: 1;
+  transform: translate(-50%, 0);
+  pointer-events: auto;
+}
+.undo-toast button {
+  border: 0;
+  background: transparent;
+  color: #74c0fc;
+  font: inherit;
+  font-weight: 700;
+  cursor: pointer;
+  padding: 2px 4px;
+}
+
 /* ---- Main ---- */
 #main { display: flex; flex: 1; overflow: hidden; }
 
@@ -843,6 +914,88 @@
 }
 #modal-confirm:hover, #export-confirm:hover { background: #1864ab; }
 
+.search-modal {
+  width: 620px;
+  max-width: 92vw;
+  padding: 0;
+  overflow: hidden;
+}
+.search-modal-head {
+  padding: 16px 18px 12px;
+  border-bottom: 1px solid #e9ecef;
+}
+#notebook-search-input {
+  width: 100%;
+  box-sizing: border-box;
+  padding: 9px 11px;
+  border: 1px solid #ced4da;
+  border-radius: 6px;
+  font-family: inherit;
+  font-size: 14px;
+  outline: none;
+}
+#notebook-search-input:focus {
+  border-color: #339af0;
+  box-shadow: 0 0 0 2px rgba(51,154,240,0.16);
+}
+#notebook-search-results {
+  max-height: 58vh;
+  overflow-y: auto;
+  padding: 8px;
+}
+.search-empty {
+  padding: 24px 14px;
+  color: #868e96;
+  text-align: center;
+  font-size: 12px;
+}
+.search-result {
+  width: 100%;
+  display: block;
+  padding: 9px 10px;
+  margin: 0 0 4px;
+  border: 1px solid transparent;
+  border-radius: 6px;
+  background: transparent;
+  cursor: pointer;
+  text-align: left;
+  font-family: inherit;
+}
+.search-result:hover,
+.search-result:focus {
+  background: #f8f9fa;
+  border-color: #dee2e6;
+  outline: none;
+}
+.search-result-meta {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  margin-bottom: 3px;
+  color: #1971c2;
+  font-size: 11px;
+  font-weight: 700;
+}
+.search-result-snippet {
+  color: #495057;
+  font-family: 'JetBrains Mono', monospace;
+  font-size: 11px;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+.search-modal-foot {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 10px;
+  padding: 8px 14px;
+  border-top: 1px solid #e9ecef;
+  color: #adb5bd;
+  font-size: 10px;
+  background: #f8f9fa;
+}
+
 .backup-desc {
   font-size: 12px;
   line-height: 1.5;
@@ -967,6 +1120,7 @@
 <div id="topbar">
   <span id="app-logo">mathnote</span>
   <div id="topbar-right">
+    <button id="search-btn" title="Search notebooks (Ctrl/Cmd+K)">Search</button>
     <button id="info-btn" title="Information / Bilgi">Info</button>
     <button id="examples-btn" title="Load examples">Examples</button>
     <button id="backup-btn" title="Backup / Restore">Backup</button>
@@ -1012,6 +1166,32 @@
   </div>
 </div>
 
+
+<div id="tab-context-menu" class="tab-context-menu" role="menu" aria-hidden="true">
+  <button type="button" data-action="rename" id="tab-menu-rename">Rename</button>
+  <button type="button" data-action="duplicate" id="tab-menu-duplicate">Duplicate</button>
+</div>
+
+<div id="undo-toast" class="undo-toast" role="status" aria-live="polite" aria-hidden="true">
+  <span id="undo-toast-text">Notebook closed.</span>
+  <button type="button" id="undo-close-btn">Undo</button>
+</div>
+
+<div id="search-modal" class="modal-overlay">
+  <div class="modal search-modal">
+    <div class="search-modal-head">
+      <div class="modal-title" id="search-modal-title">Search notebooks</div>
+      <input id="notebook-search-input" type="search" autocomplete="off" spellcheck="false"
+             placeholder="Search all notebooks...">
+    </div>
+    <div id="notebook-search-results"></div>
+    <div class="search-modal-foot">
+      <span id="search-result-count"></span>
+      <span>Esc</span>
+    </div>
+  </div>
+</div>
+
 <div id="new-file-modal" class="modal-overlay">
   <div class="modal">
     <div class="modal-title">Yeni Dosya Oluştur</div>
diff --git a/scripts/verify-offline.mjs b/scripts/verify-offline.mjs
index 9ee3752..6e0b200 100644
--- a/scripts/verify-offline.mjs
+++ b/scripts/verify-offline.mjs
@@ -60,6 +60,10 @@ if (!html.includes('rel="manifest" href="./manifest.webmanifest"')) {
 if (!html.includes('id="examples-btn"')) {
   violations.push('index.html: examples button missing');
 }
+
+for (const id of ['search-btn', 'search-modal', 'notebook-search-input', 'tab-context-menu', 'undo-toast', 'undo-close-btn']) {
+  if (!html.includes(`id="${id}"`)) violations.push(`index.html: ${id} missing`);
+}
 if (!html.includes("updateViaCache: 'none'")) {
   violations.push('index.html: service worker bootstrap must bypass HTTP cache');
 }
@@ -89,6 +93,18 @@ if (cssMatch) {
 }
 
 const sourceApp = await readFile(new URL('../src/app.js', import.meta.url), 'utf8');
+for (const symbol of [
+  'renameNotebook',
+  'duplicateNotebook',
+  'reorderNotebooks',
+  'undoCloseNotebook',
+  'openNotebookSearch',
+  'renderNotebookSearchResults',
+  "event.key.toLowerCase() === 'k'"
+]) {
+  if (!sourceApp.includes(symbol)) violations.push(`src/app.js: notebook management/search symbol missing: ${symbol}`);
+}
+
 if (sourceApp.includes("serviceWorker.register") || sourceApp.includes(".register('./sw.js'")) {
   violations.push('src/app.js: service worker registration must stay independent from app boot');
 }
diff --git a/src/app.js b/src/app.js
index 9743542..5b1acb3 100644
--- a/src/app.js
+++ b/src/app.js
@@ -22,6 +22,20 @@ const translations = {
     examplesBtn: 'Examples',
     examplesTitle: 'Load examples into a new notebook',
     examplesFileName: 'examples.math',
+    searchBtn: 'Search',
+    searchTitle: 'Search notebooks',
+    searchShortcutTitle: 'Search notebooks (Ctrl/Cmd+K)',
+    searchPlaceholder: 'Search all notebooks...',
+    searchEmpty: 'Type to search across all notebooks.',
+    searchNoResults: 'No results found.',
+    searchLine: 'line',
+    searchResults: 'results',
+    renameNotebook: 'Rename',
+    duplicateNotebook: 'Duplicate',
+    renamePrompt: 'Notebook name',
+    copySuffix: 'copy',
+    notebookClosed: 'Notebook closed.',
+    undo: 'Undo',
     
     // Modal
     modalTitle: 'Create New File',
@@ -214,6 +228,20 @@ const translations = {
     examplesBtn: 'Örnekler',
     examplesTitle: 'Örnekleri yeni bir not defterine yükle',
     examplesFileName: 'ornekler.math',
+    searchBtn: 'Ara',
+    searchTitle: 'Not defterlerinde ara',
+    searchShortcutTitle: 'Not defterlerinde ara (Ctrl/Cmd+K)',
+    searchPlaceholder: 'Tüm not defterlerinde ara...',
+    searchEmpty: 'Tüm not defterlerinde aramak için yazın.',
+    searchNoResults: 'Sonuç bulunamadı.',
+    searchLine: 'satır',
+    searchResults: 'sonuç',
+    renameNotebook: 'Yeniden adlandır',
+    duplicateNotebook: 'Kopyala',
+    renamePrompt: 'Not defteri adı',
+    copySuffix: 'kopya',
+    notebookClosed: 'Not defteri kapatıldı.',
+    undo: 'Geri Al',
     
     // Modal
     modalTitle: 'Yeni Dosya Oluştur',
@@ -424,6 +452,11 @@ function setLanguage(lang) {
 function updateUILanguage() {
   // Update tooltips
   document.getElementById('new-tab-btn').title = t('newFileBtn');
+  const searchBtn = document.getElementById('search-btn');
+  if (searchBtn) {
+    searchBtn.textContent = t('searchBtn');
+    searchBtn.title = t('searchShortcutTitle');
+  }
   const examplesBtn = document.getElementById('examples-btn');
   if (examplesBtn) {
     examplesBtn.textContent = t('examplesBtn');
@@ -443,6 +476,20 @@ function updateUILanguage() {
   document.getElementById('export-confirm').textContent = t('exportConfirm');
   document.getElementById('export-pdf-label').innerHTML = `PDF <small>${t('exportPdfHint')}</small>`;
 
+  const searchTitle = document.getElementById('search-modal-title');
+  const searchInput = document.getElementById('notebook-search-input');
+  const renameAction = document.getElementById('tab-menu-rename');
+  const duplicateAction = document.getElementById('tab-menu-duplicate');
+  const undoCloseBtn = document.getElementById('undo-close-btn');
+  if (searchTitle) searchTitle.textContent = t('searchTitle');
+  if (searchInput) searchInput.placeholder = t('searchPlaceholder');
+  if (renameAction) renameAction.textContent = t('renameNotebook');
+  if (duplicateAction) duplicateAction.textContent = t('duplicateNotebook');
+  if (undoCloseBtn) undoCloseBtn.textContent = t('undo');
+  if (document.getElementById('search-modal')?.classList.contains('active')) {
+    renderNotebookSearchResults(searchInput?.value || '');
+  }
+
   // Update backup / restore UI. These controls are optional so an older cached
   // HTML shell can still run safely while a newer JS bundle is being activated.
   const backupBtn = document.getElementById('backup-btn');
@@ -630,12 +677,114 @@ function esc(s) {
 
 // ---- Tabs ----
 
+let contextTabIndex = -1;
+let draggingTabIndex = -1;
+
+function syncActiveFileContent() {
+  if (view && files[activeIdx]) {
+    files[activeIdx].content = view.state.doc.toString();
+  }
+}
+
+function uniqueCopyName(originalName) {
+  const dot = originalName.lastIndexOf('.');
+  const hasExt = dot > 0;
+  const base = hasExt ? originalName.slice(0, dot) : originalName;
+  const ext = hasExt ? originalName.slice(dot) : '';
+  const suffix = t('copySuffix');
+
+  let candidate = base + ' ' + suffix + ext;
+  let counter = 2;
+  const names = new Set(files.map(file => file.name));
+
+  while (names.has(candidate)) {
+    candidate = base + ' ' + suffix + ' ' + counter + ext;
+    counter++;
+  }
+  return candidate;
+}
+
+function renameNotebook(idx) {
+  const file = files[idx];
+  if (!file) return;
+  syncActiveFileContent();
+  const nextName = prompt(t('renamePrompt'), file.name);
+  if (nextName === null) return;
+
+  const cleanName = nextName.trim().slice(0, 255);
+  if (!cleanName || cleanName === file.name) return;
+
+  file.name = cleanName;
+  saveNow();
+  renderTabs();
+}
+
+function duplicateNotebook(idx) {
+  const file = files[idx];
+  if (!file) return;
+  syncActiveFileContent();
+
+  const copy = {
+    name: uniqueCopyName(file.name),
+    content: file.content
+  };
+
+  files.splice(idx + 1, 0, copy);
+  activeIdx = idx + 1;
+  saveNow();
+  renderTabs();
+  replaceEditorContent(copy.content);
+}
+
+function reorderNotebooks(from, to) {
+  if (from === to || from < 0 || to < 0 || from >= files.length || to >= files.length) return;
+  syncActiveFileContent();
+
+  const activeFile = files[activeIdx];
+  const moved = files.splice(from, 1)[0];
+  files.splice(to, 0, moved);
+  activeIdx = files.indexOf(activeFile);
+
+  saveNow();
+  renderTabs();
+}
+
+function hideTabContextMenu() {
+  const menu = document.getElementById('tab-context-menu');
+  if (!menu) return;
+  menu.classList.remove('active');
+  menu.setAttribute('aria-hidden', 'true');
+  contextTabIndex = -1;
+}
+
+function showTabContextMenu(idx, x, y) {
+  const menu = document.getElementById('tab-context-menu');
+  if (!menu) return;
+
+  contextTabIndex = idx;
+  menu.classList.add('active');
+  menu.setAttribute('aria-hidden', 'false');
+  menu.style.left = '0px';
+  menu.style.top = '0px';
+
+  requestAnimationFrame(() => {
+    const rect = menu.getBoundingClientRect();
+    const left = Math.max(8, Math.min(x, window.innerWidth - rect.width - 8));
+    const top = Math.max(8, Math.min(y, window.innerHeight - rect.height - 8));
+    menu.style.left = left + 'px';
+    menu.style.top = top + 'px';
+  });
+}
+
 function renderTabs() {
   const container = document.getElementById('file-tabs');
   container.innerHTML = '';
+
   files.forEach((f, i) => {
     const tab = document.createElement('div');
     tab.className = 'file-tab' + (i === activeIdx ? ' active' : '');
+    tab.draggable = true;
+    tab.dataset.index = String(i);
 
     const nameEl = document.createElement('span');
     nameEl.className = 'name';
@@ -651,15 +800,58 @@ function renderTabs() {
     tab.appendChild(closeEl);
 
     tab.addEventListener('click', () => switchTo(i));
-    closeEl.addEventListener('click', e => { e.stopPropagation(); closeFile(i); });
+    nameEl.addEventListener('dblclick', event => {
+      event.stopPropagation();
+      renameNotebook(i);
+    });
+    closeEl.addEventListener('click', event => {
+      event.stopPropagation();
+      closeFile(i);
+    });
+
+    tab.addEventListener('contextmenu', event => {
+      event.preventDefault();
+      event.stopPropagation();
+      showTabContextMenu(i, event.clientX, event.clientY);
+    });
+
+    tab.addEventListener('dragstart', event => {
+      draggingTabIndex = i;
+      tab.classList.add('dragging');
+      hideTabContextMenu();
+      if (event.dataTransfer) {
+        event.dataTransfer.effectAllowed = 'move';
+        event.dataTransfer.setData('text/plain', String(i));
+      }
+    });
+    tab.addEventListener('dragover', event => {
+      if (draggingTabIndex < 0 || draggingTabIndex === i) return;
+      event.preventDefault();
+      tab.classList.add('drag-over');
+      if (event.dataTransfer) event.dataTransfer.dropEffect = 'move';
+    });
+    tab.addEventListener('dragleave', () => tab.classList.remove('drag-over'));
+    tab.addEventListener('drop', event => {
+      event.preventDefault();
+      tab.classList.remove('drag-over');
+      if (draggingTabIndex >= 0) reorderNotebooks(draggingTabIndex, i);
+      draggingTabIndex = -1;
+    });
+    tab.addEventListener('dragend', () => {
+      draggingTabIndex = -1;
+      document.querySelectorAll('.file-tab').forEach(el => {
+        el.classList.remove('dragging', 'drag-over');
+      });
+    });
 
     container.appendChild(tab);
   });
 }
 
 function switchTo(idx) {
+  if (!files[idx]) return;
   if (view) {
-    files[activeIdx].content = view.state.doc.toString();
+    syncActiveFileContent();
     saveNow();
   }
   activeIdx = idx;
@@ -667,6 +859,24 @@ function switchTo(idx) {
   replaceEditorContent(files[activeIdx].content);
 }
 
+document.getElementById('tab-context-menu')?.addEventListener('click', event => {
+  const button = event.target.closest('button[data-action]');
+  if (!button || contextTabIndex < 0) return;
+
+  const idx = contextTabIndex;
+  const action = button.dataset.action;
+  hideTabContextMenu();
+
+  if (action === 'rename') renameNotebook(idx);
+  if (action === 'duplicate') duplicateNotebook(idx);
+});
+
+document.addEventListener('click', event => {
+  if (!event.target.closest('#tab-context-menu')) hideTabContextMenu();
+});
+window.addEventListener('resize', hideTabContextMenu);
+window.addEventListener('scroll', hideTabContextMenu, true);
+
 let pendingNewFileContent = '';
 
 function newFile(initialContent) {
@@ -709,6 +919,163 @@ document.getElementById('new-file-input').addEventListener('keydown', e => {
   if (e.key === 'Escape') document.getElementById('new-file-modal').classList.remove('active');
 });
 
+// ── Notebook search ────────────────────────────────────────────────────────────
+const SEARCH_RESULT_LIMIT = 100;
+
+function collectNotebookSearchResults(query) {
+  const q = query.trim().toLowerCase();
+  if (!q) return [];
+
+  syncActiveFileContent();
+  const results = [];
+
+  files.forEach((file, fileIndex) => {
+    if (results.length >= SEARCH_RESULT_LIMIT) return;
+
+    if (file.name.toLowerCase().includes(q)) {
+      const firstLine = file.content.split('\n').find(line => line.trim()) || file.name;
+      results.push({
+        fileIndex,
+        lineNumber: 1,
+        snippet: firstLine.trim() || file.name,
+        fileName: file.name
+      });
+    }
+
+    const lines = file.content.split('\n');
+    for (let i = 0; i < lines.length && results.length < SEARCH_RESULT_LIMIT; i++) {
+      if (!lines[i].toLowerCase().includes(q)) continue;
+      results.push({
+        fileIndex,
+        lineNumber: i + 1,
+        snippet: lines[i].trim() || ' ',
+        fileName: file.name
+      });
+    }
+  });
+
+  return results;
+}
+
+function closeNotebookSearch() {
+  document.getElementById('search-modal')?.classList.remove('active');
+}
+
+function jumpToSearchResult(fileIndex, lineNumber, query) {
+  closeNotebookSearch();
+  switchTo(fileIndex);
+  if (!view) return;
+
+  const safeLine = Math.max(1, Math.min(lineNumber, view.state.doc.lines));
+  const line = view.state.doc.line(safeLine);
+  const q = query.trim().toLowerCase();
+  const offset = q ? line.text.toLowerCase().indexOf(q) : -1;
+  const from = offset >= 0 ? line.from + offset : line.from;
+  const to = offset >= 0 ? from + q.length : from;
+
+  view.dispatch({
+    selection: { anchor: from, head: to },
+    effects: EditorView.scrollIntoView(from, { y: 'center' })
+  });
+  view.focus();
+}
+
+function renderNotebookSearchResults(query) {
+  const container = document.getElementById('notebook-search-results');
+  const countEl = document.getElementById('search-result-count');
+  if (!container || !countEl) return;
+
+  container.innerHTML = '';
+  const cleanQuery = query.trim();
+
+  if (!cleanQuery) {
+    const empty = document.createElement('div');
+    empty.className = 'search-empty';
+    empty.textContent = t('searchEmpty');
+    container.appendChild(empty);
+    countEl.textContent = '';
+    return;
+  }
+
+  const results = collectNotebookSearchResults(cleanQuery);
+  countEl.textContent = results.length + ' ' + t('searchResults');
+
+  if (!results.length) {
+    const empty = document.createElement('div');
+    empty.className = 'search-empty';
+    empty.textContent = t('searchNoResults');
+    container.appendChild(empty);
+    return;
+  }
+
+  results.forEach(result => {
+    const button = document.createElement('button');
+    button.type = 'button';
+    button.className = 'search-result';
+
+    const meta = document.createElement('div');
+    meta.className = 'search-result-meta';
+    meta.textContent = result.fileName + ' · ' + t('searchLine') + ' ' + result.lineNumber;
+
+    const snippet = document.createElement('div');
+    snippet.className = 'search-result-snippet';
+    snippet.textContent = result.snippet;
+
+    button.appendChild(meta);
+    button.appendChild(snippet);
+    button.addEventListener('click', () => {
+      jumpToSearchResult(result.fileIndex, result.lineNumber, cleanQuery);
+    });
+
+    container.appendChild(button);
+  });
+}
+
+function openNotebookSearch() {
+  syncActiveFileContent();
+  const modal = document.getElementById('search-modal');
+  const input = document.getElementById('notebook-search-input');
+  if (!modal || !input) return;
+
+  hideTabContextMenu();
+  modal.classList.add('active');
+  input.value = '';
+  renderNotebookSearchResults('');
+  requestAnimationFrame(() => input.focus());
+}
+
+document.getElementById('search-btn')?.addEventListener('click', openNotebookSearch);
+document.getElementById('notebook-search-input')?.addEventListener('input', event => {
+  renderNotebookSearchResults(event.target.value);
+});
+document.getElementById('notebook-search-input')?.addEventListener('keydown', event => {
+  if (event.key === 'Escape') {
+    event.preventDefault();
+    closeNotebookSearch();
+  } else if (event.key === 'Enter') {
+    const first = document.querySelector('#notebook-search-results .search-result');
+    if (first) {
+      event.preventDefault();
+      first.click();
+    }
+  }
+});
+document.getElementById('search-modal')?.addEventListener('click', event => {
+  if (event.target === document.getElementById('search-modal')) closeNotebookSearch();
+});
+
+document.addEventListener('keydown', event => {
+  if ((event.ctrlKey || event.metaKey) && event.key.toLowerCase() === 'k') {
+    event.preventDefault();
+    openNotebookSearch();
+    return;
+  }
+  if (event.key === 'Escape') {
+    hideTabContextMenu();
+    closeNotebookSearch();
+  }
+});
+
 // ── Export ────────────────────────────────────────────────────────────────────
 document.getElementById('export-btn').addEventListener('click', () => {
   document.getElementById('export-modal').classList.add('active');
@@ -993,16 +1360,77 @@ document.getElementById('export-confirm').addEventListener('click', () => {
   }
 });
 
-function closeFile(idx) {
-  if (files.length === 1) { alert(t('atLeastOneFile')); return; }
-  if (!confirm(`"${files[idx].name}" ${t('confirmDelete')}`)) return;
-  files.splice(idx, 1);
-  activeIdx = Math.min(activeIdx, files.length - 1);
+let closedNotebook = null;
+let undoCloseTimer = null;
+
+function hideUndoCloseToast() {
+  const toast = document.getElementById('undo-toast');
+  if (!toast) return;
+  toast.classList.remove('active');
+  toast.setAttribute('aria-hidden', 'true');
+  if (undoCloseTimer !== null) {
+    clearTimeout(undoCloseTimer);
+    undoCloseTimer = null;
+  }
+}
+
+function showUndoCloseToast(file, index) {
+  closedNotebook = { file, index };
+  const toast = document.getElementById('undo-toast');
+  const text = document.getElementById('undo-toast-text');
+  if (!toast || !text) return;
+
+  text.textContent = file.name + ' — ' + t('notebookClosed');
+  toast.classList.add('active');
+  toast.setAttribute('aria-hidden', 'false');
+
+  if (undoCloseTimer !== null) clearTimeout(undoCloseTimer);
+  undoCloseTimer = window.setTimeout(() => {
+    closedNotebook = null;
+    hideUndoCloseToast();
+  }, 8000);
+}
+
+function undoCloseNotebook() {
+  if (!closedNotebook) return;
+  syncActiveFileContent();
+
+  const insertAt = Math.max(0, Math.min(closedNotebook.index, files.length));
+  files.splice(insertAt, 0, closedNotebook.file);
+  activeIdx = insertAt;
+  closedNotebook = null;
+
   saveNow();
   renderTabs();
   replaceEditorContent(files[activeIdx].content);
+  hideUndoCloseToast();
+}
+
+function closeFile(idx) {
+  if (files.length === 1) {
+    alert(t('atLeastOneFile'));
+    return;
+  }
+
+  syncActiveFileContent();
+  const oldActiveIdx = activeIdx;
+  const removed = files.splice(idx, 1)[0];
+  if (!removed) return;
+
+  if (idx < oldActiveIdx) {
+    activeIdx = oldActiveIdx - 1;
+  } else if (idx === oldActiveIdx) {
+    activeIdx = Math.min(idx, files.length - 1);
+  }
+
+  saveNow();
+  renderTabs();
+  if (idx === oldActiveIdx) replaceEditorContent(files[activeIdx].content);
+  showUndoCloseToast(removed, idx);
 }
 
+document.getElementById('undo-close-btn')?.addEventListener('click', undoCloseNotebook);
+
 document.getElementById('new-tab-btn').addEventListener('click', newFile);
 
 // ================================================================