diff --git a/src/index.html b/src/index.html
index c31305a..b52411e 100644
--- a/src/index.html
+++ b/src/index.html
@@ -22,6 +22,7 @@
   <div id="app-content">
 
   <div id="view-home">
+    <img class="home-logo" src="assets/icon.png" alt="Pena" />
     <h1 class="home-title">Pena</h1>
     <div class="home-buttons">
       <button id="btn-open-file">Ouvrir un fichier Markdown</button>
@@ -47,6 +48,7 @@
         </button>
         <button id="btn-back" class="btn-back">← Accueil</button>
       </div>
+      <div id="sidebar-resizer" class="sidebar__resizer" title="Redimensionner"></div>
     </div>
     <div id="content" class="content">
       <!-- contenu généré par JS -->
diff --git a/src/main.js b/src/main.js
index f6182ac..aaa84ba 100644
--- a/src/main.js
+++ b/src/main.js
@@ -1,5 +1,6 @@
-import { showHome, openPath } from './router.js';
+import { showHome, openPath, initWatcher } from './router.js';
 import { initCssModal } from './ui/css-modal.js';
+import { initSidebarResize } from './ui/sidebar-resize.js';
 
 const win = window.__TAURI__.window.getCurrentWindow();
 
@@ -33,4 +34,6 @@ document.getElementById('btn-open-dir').addEventListener('click', async () => {
 document.getElementById('btn-back').addEventListener('click', showHome);
 
 await initCssModal();
+initSidebarResize();
+await initWatcher();
 showHome();
diff --git a/src/router.js b/src/router.js
index d3f5bad..ba3371f 100644
--- a/src/router.js
+++ b/src/router.js
@@ -1,5 +1,6 @@
 import { appState } from './state/app-state.js';
 import { listMdFiles } from './services/files.js';
+import { startWatch, stopWatch, onFileChanged } from './services/watcher.js';
 import { renderSidebar } from './ui/sidebar.js';
 import { loadPage } from './ui/reader.js';
 import { saveRecent, renderRecents } from './ui/home.js';
@@ -11,9 +12,15 @@ const content = document.querySelector('#content');
 const win = window.__TAURI__.window.getCurrentWindow();
 const titlebarTitle = document.getElementById('titlebar-title');
 
+const navigate = filePath => loadPage(filePath, appState.currentMode, sidebarEl);
+
 export function showHome() {
+  stopWatch();
   appState.currentPath = null;
   appState.currentMode = null;
+  appState.baseDir = null;
+  appState.currentFile = null;
+  appState.files = [];
   sidebarEl.innerHTML = '';
   win.setTitle('Pena — Markdown Viewer');
   titlebarTitle.textContent = 'Pena — Markdown Viewer';
@@ -38,15 +45,21 @@ export async function openPath(path, mode) {
     const parentDir = path.split(sep).slice(0, -1).join(sep);
     try {
       const files = await listMdFiles(parentDir);
+      appState.baseDir = parentDir;
+      appState.files = files;
       sidebarEl.classList.remove('hidden');
       content.style.marginLeft = '';
-      renderSidebar(parentDir, files, path, filePath => loadPage(filePath, appState.currentMode, sidebarEl));
+      renderSidebar(parentDir, files, path, navigate);
     } catch {
+      // Le dossier parent est illisible : on surveille au moins le fichier ouvert.
+      appState.baseDir = path;
+      appState.files = [];
       sidebarEl.innerHTML = '';
       sidebarEl.classList.add('hidden');
       content.style.marginLeft = '0';
     }
     await loadPage(path, appState.currentMode, sidebarEl);
+    startWatch(appState.baseDir);
     return;
   }
 
@@ -56,6 +69,8 @@ export async function openPath(path, mode) {
 
   try {
     const files = await listMdFiles(path);
+    appState.baseDir = path;
+    appState.files = files;
     showReader();
 
     const sep = path.includes('\\') ? '\\' : '/';
@@ -65,10 +80,48 @@ export async function openPath(path, mode) {
     });
 
     const firstFile = home ?? files[0];
-    renderSidebar(path, files, firstFile, filePath => loadPage(filePath, appState.currentMode, sidebarEl));
+    renderSidebar(path, files, firstFile, navigate);
     await loadPage(firstFile, appState.currentMode, sidebarEl);
+    startWatch(path);
   } catch (err) {
     showReader();
     content.innerHTML = `<p class="error">Impossible d'ouvrir le dossier : ${err}</p>`;
   }
 }
+
+// Compare deux listes de fichiers indépendamment de l'ordre.
+function sameFiles(a, b) {
+  if (a.length !== b.length) return false;
+  const key = arr => arr.slice().sort().join('\n');
+  return key(a) === key(b);
+}
+
+// Réaction à un changement filesystem signalé par le backend (événement débouncé,
+// filtré sur les fichiers .md).
+async function handleFileChanged(changedPath) {
+  if (!appState.baseDir || !appState.currentMode) return;
+
+  // Rafraîchir la sidebar uniquement si l'arborescence a changé (ajout/suppression),
+  // pour ne pas replier les dossiers ouverts à chaque simple modification de contenu.
+  try {
+    const files = await listMdFiles(appState.baseDir);
+    if (!sameFiles(files, appState.files)) {
+      appState.files = files;
+      renderSidebar(appState.baseDir, files, appState.currentFile, navigate);
+    }
+  } catch {
+    // baseDir supprimé/illisible : on garde la sidebar en l'état.
+  }
+
+  // Recharger le document affiché si c'est lui qui vient d'être modifié.
+  if (changedPath === appState.currentFile) {
+    await loadPage(appState.currentFile, appState.currentMode, sidebarEl);
+  }
+}
+
+// À appeler une fois au démarrage : enregistre le listener global de changements.
+export function initWatcher() {
+  return onFileChanged(event => {
+    handleFileChanged(event.payload.path);
+  });
+}
diff --git a/src/state/app-state.js b/src/state/app-state.js
index a81822b..6458599 100644
--- a/src/state/app-state.js
+++ b/src/state/app-state.js
@@ -1 +1,12 @@
-export const appState = { currentPath: null, currentMode: null };
+export const appState = {
+  currentPath: null,
+  currentMode: null,
+  // Dossier réellement surveillé (racine de la sidebar) : le dossier ouvert en
+  // mode « dir », ou le dossier parent du fichier ouvert en mode « file ».
+  baseDir: null,
+  // Fichier actuellement affiché dans le lecteur.
+  currentFile: null,
+  // Dernière liste de fichiers .md connue de `baseDir`, pour détecter les
+  // ajouts/suppressions et ne rafraîchir la sidebar que si l'arborescence change.
+  files: [],
+};
diff --git a/src/ui/reader.js b/src/ui/reader.js
index f96b9bd..318542c 100644
--- a/src/ui/reader.js
+++ b/src/ui/reader.js
@@ -1,4 +1,5 @@
 import { convertFile } from '../services/markdown.js';
+import { appState } from '../state/app-state.js';
 
 const win = window.__TAURI__.window.getCurrentWindow();
 const titlebarTitle = document.getElementById('titlebar-title');
@@ -69,6 +70,7 @@ function addCopyButtons() {
 export async function loadPage(filePath, mode, sidebarEl) {
   try {
     const html = await convertFile(filePath);
+    appState.currentFile = filePath;
     content.innerHTML = html;
     addCopyButtons();
 
diff --git a/src/ui/sidebar-resize.js b/src/ui/sidebar-resize.js
new file mode 100644
index 0000000..1178310
--- /dev/null
+++ b/src/ui/sidebar-resize.js
@@ -0,0 +1,49 @@
+const STORAGE_KEY = 'pena.sidebarWidth';
+const MIN_WIDTH = 180;
+const MAX_WIDTH = 520;
+
+function clamp(width) {
+  return Math.min(MAX_WIDTH, Math.max(MIN_WIDTH, width));
+}
+
+function applyWidth(width) {
+  document.documentElement.style.setProperty('--sidebar-width', `${width}px`);
+}
+
+export function initSidebarResize() {
+  const handle = document.getElementById('sidebar-resizer');
+  if (!handle) return;
+
+  const stored = parseInt(localStorage.getItem(STORAGE_KEY), 10);
+  if (!Number.isNaN(stored)) applyWidth(clamp(stored));
+
+  let dragging = false;
+
+  const onMove = (e) => {
+    if (!dragging) return;
+    applyWidth(clamp(e.clientX));
+  };
+
+  const onUp = () => {
+    if (!dragging) return;
+    dragging = false;
+    handle.classList.remove('is-dragging');
+    document.body.classList.remove('is-resizing-sidebar');
+    const width = parseInt(
+      getComputedStyle(document.documentElement).getPropertyValue('--sidebar-width'),
+      10,
+    );
+    if (!Number.isNaN(width)) localStorage.setItem(STORAGE_KEY, String(width));
+    window.removeEventListener('mousemove', onMove);
+    window.removeEventListener('mouseup', onUp);
+  };
+
+  handle.addEventListener('mousedown', (e) => {
+    e.preventDefault();
+    dragging = true;
+    handle.classList.add('is-dragging');
+    document.body.classList.add('is-resizing-sidebar');
+    window.addEventListener('mousemove', onMove);
+    window.addEventListener('mouseup', onUp);
+  });
+}