diff --git a/backend/main.py b/backend/main.py
index 9823b90..19206cf 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -195,6 +195,39 @@ async def api_file_download(vault_name: str, path: str = Query(..., description=
     )
 
 
+@app.put("/api/file/{vault_name}/save")
+async def api_file_save(vault_name: str, path: str = Query(..., description="Relative path to file"), body: dict = {}):
+    """Save file content."""
+    vault_data = get_vault_data(vault_name)
+    if not vault_data:
+        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
+
+    vault_root = Path(vault_data["path"])
+    file_path = vault_root / path
+
+    # Security: ensure path is within vault
+    try:
+        file_path.resolve().relative_to(vault_root.resolve())
+    except ValueError:
+        raise HTTPException(status_code=403, detail="Access denied: path outside vault")
+
+    if not file_path.exists():
+        raise HTTPException(status_code=404, detail=f"File not found: {path}")
+
+    # Get content from body
+    content = body.get('content', '')
+    
+    try:
+        file_path.write_text(content, encoding="utf-8")
+        logger.info(f"File saved: {vault_name}/{path}")
+        return {"status": "ok", "vault": vault_name, "path": path, "size": len(content)}
+    except PermissionError:
+        raise HTTPException(status_code=403, detail="Permission denied: vault may be read-only")
+    except Exception as e:
+        logger.error(f"Error saving file {vault_name}/{path}: {e}")
+        raise HTTPException(status_code=500, detail=f"Error saving file: {str(e)}")
+
+
 @app.get("/api/file/{vault_name}")
 async def api_file(vault_name: str, path: str = Query(..., description="Relative path to file")):
     """Return rendered HTML + metadata for a file."""
diff --git a/frontend/app.js b/frontend/app.js
index 14d3c69..89ec9ae 100644
--- a/frontend/app.js
+++ b/frontend/app.js
@@ -13,6 +13,9 @@
   let cachedRawSource = null;
   let allVaults = [];
   let selectedContextVault = "all";
+  let editorView = null;
+  let editorVault = null;
+  let editorPath = null;
 
   // ---------------------------------------------------------------------------
   // File extension → Lucide icon mapping
@@ -476,6 +479,14 @@
       document.body.removeChild(a);
     });
 
+    const editBtn = el("button", { class: "btn-action", title: "Éditer" }, [
+      icon("edit", 14),
+      document.createTextNode("Éditer"),
+    ]);
+    editBtn.addEventListener("click", () => {
+      openEditor(data.vault, data.path);
+    });
+
     // Frontmatter
     let fmSection = null;
     if (data.frontmatter && Object.keys(data.frontmatter).length > 0) {
@@ -529,7 +540,7 @@
     area.appendChild(el("div", { class: "file-header" }, [
       el("div", { class: "file-title" }, [document.createTextNode(data.title)]),
       tagsDiv,
-      el("div", { class: "file-actions" }, [copyBtn, sourceBtn, downloadBtn]),
+      el("div", { class: "file-actions" }, [copyBtn, sourceBtn, downloadBtn, editBtn]),
     ]));
     if (fmSection) area.appendChild(fmSection);
     area.appendChild(mdDiv);
@@ -574,6 +585,8 @@
   }
 
   async function performSearch(query, vaultFilter, tagFilter) {
+    showLoading();
+    
     let url = `/api/search?q=${encodeURIComponent(query)}&vault=${encodeURIComponent(vaultFilter)}`;
     if (tagFilter) url += `&tag=${encodeURIComponent(tagFilter)}`;
 
@@ -754,18 +767,196 @@
     safeCreateIcons();
   }
 
+  function showLoading() {
+    const area = document.getElementById("content-area");
+    area.innerHTML = `
+      <div class="loading-indicator">
+        <div class="loading-spinner"></div>
+        <div>Recherche en cours...</div>
+      </div>`;
+  }
+
+  function goHome() {
+    const searchInput = document.getElementById("search-input");
+    if (searchInput) searchInput.value = "";
+    
+    document.querySelectorAll(".tree-item.active").forEach((el) => el.classList.remove("active"));
+    
+    currentVault = null;
+    currentPath = null;
+    showingSource = false;
+    cachedRawSource = null;
+    
+    closeMobileSidebar();
+    showWelcome();
+  }
+
+  // ---------------------------------------------------------------------------
+  // Editor (CodeMirror)
+  // ---------------------------------------------------------------------------
+  async function openEditor(vaultName, filePath) {
+    editorVault = vaultName;
+    editorPath = filePath;
+
+    const modal = document.getElementById("editor-modal");
+    const titleEl = document.getElementById("editor-title");
+    const bodyEl = document.getElementById("editor-body");
+
+    titleEl.textContent = `Édition: ${filePath.split("/").pop()}`;
+
+    // Fetch raw content
+    const rawUrl = `/api/file/${encodeURIComponent(vaultName)}/raw?path=${encodeURIComponent(filePath)}`;
+    const rawData = await api(rawUrl);
+
+    // Clear previous editor
+    bodyEl.innerHTML = "";
+    if (editorView) {
+      editorView.destroy();
+      editorView = null;
+    }
+
+    // Wait for CodeMirror to be available
+    await waitForCodeMirror();
+
+    const { EditorView, EditorState, basicSetup, markdown, oneDark, keymap } = window.CodeMirror;
+
+    // Determine theme
+    const currentTheme = document.documentElement.getAttribute("data-theme");
+    const extensions = [
+      basicSetup,
+      markdown(),
+      keymap.of([{
+        key: "Mod-s",
+        run: () => {
+          saveFile();
+          return true;
+        }
+      }]),
+      EditorView.lineWrapping,
+    ];
+
+    if (currentTheme === "dark") {
+      extensions.push(oneDark);
+    }
+
+    const state = EditorState.create({
+      doc: rawData.raw,
+      extensions: extensions,
+    });
+
+    editorView = new EditorView({
+      state: state,
+      parent: bodyEl,
+    });
+
+    modal.classList.add("active");
+    safeCreateIcons();
+  }
+
+  async function waitForCodeMirror() {
+    let attempts = 0;
+    while (!window.CodeMirror && attempts < 50) {
+      await new Promise(resolve => setTimeout(resolve, 100));
+      attempts++;
+    }
+    if (!window.CodeMirror) {
+      throw new Error("CodeMirror failed to load");
+    }
+  }
+
+  function closeEditor() {
+    const modal = document.getElementById("editor-modal");
+    modal.classList.remove("active");
+    if (editorView) {
+      editorView.destroy();
+      editorView = null;
+    }
+    editorVault = null;
+    editorPath = null;
+  }
+
+  async function saveFile() {
+    if (!editorView || !editorVault || !editorPath) return;
+
+    const content = editorView.state.doc.toString();
+    const saveBtn = document.getElementById("editor-save");
+    const originalText = saveBtn.textContent;
+
+    try {
+      saveBtn.disabled = true;
+      saveBtn.innerHTML = '<i data-lucide="loader" style="width:14px;height:14px"></i> Sauvegarde...';
+      safeCreateIcons();
+
+      const response = await fetch(
+        `/api/file/${encodeURIComponent(editorVault)}/save?path=${encodeURIComponent(editorPath)}`,
+        {
+          method: "PUT",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ content: content }),
+        }
+      );
+
+      if (!response.ok) {
+        const error = await response.json();
+        throw new Error(error.detail || "Erreur de sauvegarde");
+      }
+
+      saveBtn.innerHTML = '<i data-lucide="check" style="width:14px;height:14px"></i> Sauvegardé !';
+      safeCreateIcons();
+
+      setTimeout(() => {
+        closeEditor();
+        // Reload the file if it's currently open
+        if (currentVault === editorVault && currentPath === editorPath) {
+          openFile(currentVault, currentPath);
+        }
+      }, 800);
+    } catch (err) {
+      console.error("Save error:", err);
+      alert(`Erreur: ${err.message}`);
+      saveBtn.innerHTML = originalText;
+      saveBtn.disabled = false;
+      safeCreateIcons();
+    }
+  }
+
+  function initEditor() {
+    const cancelBtn = document.getElementById("editor-cancel");
+    const saveBtn = document.getElementById("editor-save");
+    const modal = document.getElementById("editor-modal");
+
+    cancelBtn.addEventListener("click", closeEditor);
+    saveBtn.addEventListener("click", saveFile);
+
+    // Close on overlay click
+    modal.addEventListener("click", (e) => {
+      if (e.target === modal) {
+        closeEditor();
+      }
+    });
+
+    // ESC to close
+    document.addEventListener("keydown", (e) => {
+      if (e.key === "Escape" && modal.classList.contains("active")) {
+        closeEditor();
+      }
+    });
+  }
+
   // ---------------------------------------------------------------------------
   // Init
   // ---------------------------------------------------------------------------
   async function init() {
     initTheme();
     document.getElementById("theme-toggle").addEventListener("click", toggleTheme);
+    document.getElementById("header-logo").addEventListener("click", goHome);
     initSearch();
     initMobile();
     initVaultContext();
     initSidebarFilter();
     initSidebarResize();
     initTagResize();
+    initEditor();
 
     try {
       await Promise.all([loadVaults(), loadTags()]);
diff --git a/frontend/index.html b/frontend/index.html
index 9bc0249..208e8bb 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -9,6 +9,16 @@
   <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github.min.css" id="hljs-theme-light" disabled>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js"></script>
   <script src="https://unpkg.com/lucide@0.344.0/dist/umd/lucide.min.js"></script>
+  
+  <!-- CodeMirror 6 -->
+  <script type="module">
+    import { EditorView, basicSetup } from "https://esm.sh/@codemirror/basic-setup@0.20.0";
+    import { EditorState } from "https://esm.sh/@codemirror/state@6.2.0";
+    import { markdown } from "https://esm.sh/@codemirror/lang-markdown@6.1.0";
+    import { oneDark } from "https://esm.sh/@codemirror/theme-one-dark@6.1.0";
+    import { keymap } from "https://esm.sh/@codemirror/view@6.9.0";
+    window.CodeMirror = { EditorView, EditorState, basicSetup, markdown, oneDark, keymap };
+  </script>
 </head>
 <body>
   <div class="app-container">
@@ -19,7 +29,7 @@
         <i data-lucide="menu" style="width:20px;height:20px"></i>
       </button>
 
-      <div class="header-logo">
+      <div class="header-logo" id="header-logo">
         <i data-lucide="book-open" style="width:20px;height:20px"></i>
         ObsiGate
       </div>
@@ -81,6 +91,26 @@
     </div>
   </div>
 
+  <!-- Editor Modal -->
+  <div class="editor-modal" id="editor-modal">
+    <div class="editor-container">
+      <div class="editor-header">
+        <div class="editor-title" id="editor-title">Édition</div>
+        <div class="editor-actions">
+          <button class="editor-btn" id="editor-cancel">
+            <i data-lucide="x" style="width:14px;height:14px"></i>
+            Annuler
+          </button>
+          <button class="editor-btn primary" id="editor-save">
+            <i data-lucide="save" style="width:14px;height:14px"></i>
+            Sauvegarder
+          </button>
+        </div>
+      </div>
+      <div class="editor-body" id="editor-body"></div>
+    </div>
+  </div>
+
   <script src="/static/app.js"></script>
 </body>
 </html>
diff --git a/frontend/style.css b/frontend/style.css
index 2c4127c..71a9c55 100644
--- a/frontend/style.css
+++ b/frontend/style.css
@@ -118,6 +118,13 @@ a:hover {
   display: flex;
   align-items: center;
   gap: 8px;
+  cursor: pointer;
+  transition: opacity 200ms ease;
+  text-decoration: none;
+}
+.header-logo:hover {
+  opacity: 0.8;
+  text-decoration: none;
 }
 
 .search-wrapper {
@@ -741,6 +748,150 @@ a:hover {
   padding: 1px 6px;
 }
 
+/* --- Loading indicator --- */
+.loading-indicator {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  padding: 40px 20px;
+  color: var(--text-muted);
+  gap: 12px;
+}
+.loading-spinner {
+  width: 32px;
+  height: 32px;
+  border: 3px solid var(--border);
+  border-top-color: var(--accent);
+  border-radius: 50%;
+  animation: spin 0.8s linear infinite;
+}
+@keyframes spin {
+  to { transform: rotate(360deg); }
+}
+
+/* --- Editor Modal --- */
+.editor-modal {
+  display: none;
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  z-index: 1000;
+  background: var(--overlay-bg);
+  align-items: center;
+  justify-content: center;
+  padding: 20px;
+}
+.editor-modal.active {
+  display: flex;
+}
+
+.editor-container {
+  background: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: 12px;
+  width: 100%;
+  max-width: 1200px;
+  max-height: 90vh;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
+}
+
+.editor-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 12px 16px;
+  border-bottom: 1px solid var(--border);
+  background: var(--bg-primary);
+  flex-shrink: 0;
+}
+
+.editor-title {
+  font-family: 'JetBrains Mono', monospace;
+  font-size: 0.9rem;
+  color: var(--text-primary);
+  font-weight: 600;
+}
+
+.editor-actions {
+  display: flex;
+  gap: 8px;
+}
+
+.editor-btn {
+  font-family: 'JetBrains Mono', monospace;
+  font-size: 0.8rem;
+  padding: 6px 12px;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  background: transparent;
+  color: var(--text-secondary);
+  cursor: pointer;
+  transition: all 150ms ease;
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+}
+.editor-btn:hover {
+  color: var(--accent);
+  border-color: var(--accent);
+}
+.editor-btn.primary {
+  background: var(--accent);
+  color: #ffffff;
+  border-color: var(--accent);
+}
+.editor-btn.primary:hover {
+  opacity: 0.9;
+}
+
+.editor-body {
+  flex: 1;
+  overflow: hidden;
+  position: relative;
+}
+
+.cm-editor {
+  height: 100%;
+  font-size: 0.9rem;
+}
+
+.cm-scroller {
+  font-family: 'JetBrains Mono', monospace;
+}
+
+/* Mobile editor */
+@media (max-width: 768px) {
+  .editor-modal {
+    padding: 0;
+  }
+  
+  .editor-container {
+    max-width: 100%;
+    max-height: 100vh;
+    border-radius: 0;
+    height: 100vh;
+  }
+  
+  .editor-header {
+    padding: 10px 12px;
+  }
+  
+  .editor-title {
+    font-size: 0.85rem;
+  }
+  
+  .editor-btn {
+    font-size: 0.75rem;
+    padding: 5px 10px;
+  }
+}
+
 /* --- No-select during resize --- */
 body.resizing {
   user-select: none;
@@ -768,12 +919,13 @@ body.resizing-v {
   }
 
   .header {
-    gap: 8px;
-    padding: 8px 12px;
+    gap: 6px;
+    padding: 8px 10px;
   }
 
   .header-logo {
-    font-size: 1rem;
+    font-size: 0.95rem;
+    gap: 6px;
   }
 
   .search-wrapper {
@@ -781,9 +933,14 @@ body.resizing-v {
     flex: 1;
   }
 
+  .search-wrapper input {
+    padding: 6px 10px 6px 32px;
+    font-size: 0.8rem;
+  }
+
   .search-vault-filter {
-    font-size: 0.72rem;
-    padding: 5px 6px;
+    font-size: 0.7rem;
+    padding: 4px 6px;
   }
 
   .sidebar {
@@ -808,6 +965,16 @@ body.resizing-v {
     display: none;
   }
 
+  .tag-resize-handle {
+    display: none;
+  }
+
+  .tag-cloud-section {
+    height: auto;
+    max-height: 200px;
+    min-height: 80px;
+  }
+
   .content-area {
     padding: 16px 12px 60px;
   }