diff --git a/app.py b/app.py
index ab5e49a..603f95e 100644
--- a/app.py
+++ b/app.py
@@ -3494,6 +3494,91 @@ def delete_project_file(filename):
     return redirect(url_for('files'))
 
 
+@app.route('/files/project/save/<filename>', methods=['POST'])
+@login_required
+def save_project_file(filename):
+    """Speichert den Inhalt einer Projektdatei (JSON POST)."""
+    base_dir = os.path.dirname(__file__)
+    filepath = os.path.join(base_dir, filename)
+    if os.path.dirname(os.path.abspath(filepath)) != os.path.abspath(base_dir):
+        return jsonify({'ok': False, 'error': 'Zugriff verweigert'}), 403
+    if not filename.lower().endswith(('.md', '.txt')):
+        return jsonify({'ok': False, 'error': 'Nur .md und .txt Dateien editierbar'}), 400
+    try:
+        data = request.get_json()
+        content = data.get('content', '') if data else ''
+        with open(filepath, 'w', encoding='utf-8') as f:
+            f.write(content)
+        return jsonify({'ok': True})
+    except Exception as e:
+        return jsonify({'ok': False, 'error': str(e)}), 500
+
+
+@app.route('/files/agent/<agent_key>/save/<filename>', methods=['POST'])
+@login_required
+def save_agent_file(agent_key, filename):
+    """Speichert den Inhalt einer Agent-Datei (JSON POST)."""
+    agents_base = os.path.join(os.path.dirname(__file__), 'agents')
+    work_dir = os.path.join(agents_base, agent_key, 'work')
+    filepath = os.path.join(work_dir, filename)
+    if not os.path.abspath(filepath).startswith(os.path.abspath(work_dir)):
+        return jsonify({'ok': False, 'error': 'Zugriff verweigert'}), 403
+    if not filename.lower().endswith(('.md', '.txt', '.json', '.csv')):
+        return jsonify({'ok': False, 'error': 'Dateityp nicht editierbar'}), 400
+    try:
+        data = request.get_json()
+        content = data.get('content', '') if data else ''
+        with open(filepath, 'w', encoding='utf-8') as f:
+            f.write(content)
+        return jsonify({'ok': True})
+    except Exception as e:
+        return jsonify({'ok': False, 'error': str(e)}), 500
+
+
+@app.route('/files/editor')
+@login_required
+def file_editor():
+    """Vollbild-Editor für Dateien (Email-Vorlagen, Projektdokumente, Agent-Dateien)."""
+    file_type = request.args.get('type', 'email')   # email | project | agent
+    filename   = request.args.get('name', '')
+    agent_key  = request.args.get('agent', '')
+
+    # Inhalt laden
+    content = ''
+    error = ''
+    try:
+        base = os.path.dirname(__file__)
+        if file_type == 'email':
+            fp = os.path.join(base, 'emails', filename)
+            safe = os.path.abspath(fp).startswith(os.path.abspath(os.path.join(base, 'emails')))
+        elif file_type == 'project':
+            fp = os.path.join(base, filename)
+            safe = os.path.dirname(os.path.abspath(fp)) == os.path.abspath(base)
+        elif file_type == 'agent':
+            fp = os.path.join(base, 'agents', agent_key, 'work', filename)
+            safe = os.path.abspath(fp).startswith(os.path.abspath(os.path.join(base, 'agents', agent_key, 'work')))
+        else:
+            safe = False
+
+        if not safe:
+            error = 'Zugriff verweigert'
+        elif not os.path.isfile(fp):
+            error = 'Datei nicht gefunden'
+        else:
+            with open(fp, 'r', encoding='utf-8', errors='replace') as f:
+                content = f.read()
+    except Exception as e:
+        error = str(e)
+
+    return render_template('file_editor.html',
+        file_type=file_type,
+        filename=filename,
+        agent_key=agent_key,
+        content=content,
+        error=error,
+    )
+
+
 @app.route('/emails', methods=['GET', 'POST'])
 @login_required
 def emails():
diff --git a/templates/file_editor.html b/templates/file_editor.html
new file mode 100644
index 0000000..cc4da7d
--- /dev/null
+++ b/templates/file_editor.html
@@ -0,0 +1,179 @@
+{% extends "base.html" %}
+{% block title %}Editor · {{ filename }}{% endblock %}
+
+{% block head %}
+<style>
+  /* Vollbild-Editor Layout */
+  .editor-wrap {
+    display: flex;
+    flex-direction: column;
+    height: calc(100vh - 130px);
+    gap: .75rem;
+  }
+  .editor-topbar {
+    display: flex;
+    align-items: center;
+    gap: .75rem;
+    flex-shrink: 0;
+    flex-wrap: wrap;
+  }
+  .editor-meta {
+    flex: 1;
+    min-width: 0;
+  }
+  .editor-filename {
+    font-size: 1rem;
+    font-weight: 600;
+    font-family: 'JetBrains Mono', monospace;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+  }
+  .editor-breadcrumb {
+    font-size: .75rem;
+    color: var(--text-muted);
+    margin-top: .1rem;
+  }
+  #editor-textarea {
+    flex: 1;
+    width: 100%;
+    resize: none;
+    background: var(--bg-base);
+    color: var(--text-primary);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    padding: 1.1rem 1.25rem;
+    font-family: 'JetBrains Mono', monospace;
+    font-size: .875rem;
+    line-height: 1.65;
+    outline: none;
+    transition: border-color .15s;
+    tab-size: 2;
+  }
+  #editor-textarea:focus {
+    border-color: var(--accent);
+    box-shadow: 0 0 0 2px rgba(99,102,241,.15);
+  }
+  .editor-statusbar {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    font-size: .75rem;
+    color: var(--text-muted);
+    flex-shrink: 0;
+    padding: 0 .1rem;
+  }
+  #save-status {
+    font-weight: 500;
+    min-width: 120px;
+    text-align: right;
+  }
+</style>
+{% endblock %}
+
+{% block content %}
+{% if error %}
+<div class="alert alert-danger">{{ error }}</div>
+<a href="/files" class="btn btn-secondary">← Zurück zu Dateien</a>
+{% else %}
+
+<div class="editor-wrap">
+  <!-- Topbar -->
+  <div class="editor-topbar">
+    <a href="/files" class="btn btn-outline-secondary btn-sm">← Zurück</a>
+    <div class="editor-meta">
+      <div class="editor-filename">{{ filename }}</div>
+      <div class="editor-breadcrumb">
+        {% if file_type == 'email' %}✉ Email-Vorlage · emails/{{ filename }}
+        {% elif file_type == 'project' %}📄 Projektdokument · {{ filename }}
+        {% elif file_type == 'agent' %}🤖 {{ agent_key }} · agents/{{ agent_key }}/work/{{ filename }}
+        {% endif %}
+      </div>
+    </div>
+    <button id="save-btn" class="btn btn-primary btn-sm" onclick="saveFile()">💾 Speichern</button>
+  </div>
+
+  <!-- Editor -->
+  <textarea id="editor-textarea" spellcheck="false">{{ content }}</textarea>
+
+  <!-- Statusbar -->
+  <div class="editor-statusbar">
+    <span id="cursor-pos">Zeile 1, Spalte 1</span>
+    <span id="save-status"></span>
+  </div>
+</div>
+
+<script>
+const FILE_TYPE  = {{ file_type|tojson }};
+const FILENAME   = {{ filename|tojson }};
+const AGENT_KEY  = {{ agent_key|tojson }};
+
+const ta = document.getElementById('editor-textarea');
+const saveStatus = document.getElementById('save-status');
+const cursorPos  = document.getElementById('cursor-pos');
+
+// Cursor-Position anzeigen
+ta.addEventListener('keyup', updateCursor);
+ta.addEventListener('click', updateCursor);
+function updateCursor() {
+  const text = ta.value.substring(0, ta.selectionStart);
+  const line = text.split('\n').length;
+  const col  = text.split('\n').pop().length + 1;
+  cursorPos.textContent = `Zeile ${line}, Spalte ${col}`;
+}
+
+// Tab-Taste einfügen statt Fokus verlieren
+ta.addEventListener('keydown', function(e) {
+  if (e.key === 'Tab') {
+    e.preventDefault();
+    const s = ta.selectionStart, end = ta.selectionEnd;
+    ta.value = ta.value.substring(0, s) + '  ' + ta.value.substring(end);
+    ta.selectionStart = ta.selectionEnd = s + 2;
+  }
+  // Ctrl/Cmd+S → Speichern
+  if ((e.ctrlKey || e.metaKey) && e.key === 's') {
+    e.preventDefault();
+    saveFile();
+  }
+});
+
+// Speichern
+function saveFile() {
+  const btn = document.getElementById('save-btn');
+  btn.disabled = true;
+  saveStatus.style.color = 'var(--text-muted)';
+  saveStatus.textContent = 'Speichern…';
+
+  let url;
+  if (FILE_TYPE === 'email')   url = '/files/email/save/'   + encodeURIComponent(FILENAME);
+  if (FILE_TYPE === 'project') url = '/files/project/save/' + encodeURIComponent(FILENAME);
+  if (FILE_TYPE === 'agent')   url = '/files/agent/' + encodeURIComponent(AGENT_KEY) + '/save/' + encodeURIComponent(FILENAME);
+
+  fetch(url, {
+    method: 'POST',
+    credentials: 'same-origin',
+    headers: {'Content-Type': 'application/json'},
+    body: JSON.stringify({content: ta.value})
+  })
+  .then(r => r.json())
+  .then(d => {
+    if (d.ok) {
+      saveStatus.style.color = 'var(--success, #22c55e)';
+      saveStatus.textContent = '✓ Gespeichert';
+      setTimeout(() => { saveStatus.textContent = ''; }, 3000);
+    } else {
+      saveStatus.style.color = 'var(--danger, #ef4444)';
+      saveStatus.textContent = '✗ ' + (d.error || 'Fehler');
+    }
+  })
+  .catch(err => {
+    saveStatus.style.color = 'var(--danger, #ef4444)';
+    saveStatus.textContent = '✗ ' + err.message;
+  })
+  .finally(() => { btn.disabled = false; });
+}
+
+updateCursor();
+</script>
+{% endif %}
+{% endblock %}
diff --git a/templates/files.html b/templates/files.html
index c1eff31..68113a4 100644
--- a/templates/files.html
+++ b/templates/files.html
@@ -103,8 +103,7 @@
             <div class="file-actions">
               <button class="btn btn-sm btn-secondary"
                 onclick="viewEmailFile(event, '{{ file.name }}')" title="Anzeigen">👁</button>
-              <button class="btn btn-sm btn-primary"
-                onclick="editEmailFile('{{ file.name }}')" title="Bearbeiten">✎</button>
+              <a href="/files/editor?type=email&name={{ file.name|urlencode }}" class="btn btn-sm btn-primary" title="Bearbeiten">✎</a>
               <a href="/files/email/delete/{{ file.name }}" class="btn btn-sm btn-danger"
                 onclick="return confirm('Email-Vorlage löschen?')" title="Löschen">✕</a>
             </div>
@@ -137,7 +136,11 @@
             <div class="file-actions">
               <button class="btn btn-sm btn-secondary"
                 onclick="viewProjectFile(event, '{{ file.name }}')" title="Anzeigen">👁</button>
+              {% if file.name.lower().endswith(('.md', '.txt')) %}
+              <a href="/files/editor?type=project&name={{ file.name|urlencode }}" class="btn btn-sm btn-primary" title="Bearbeiten">✎</a>
+              {% else %}
               <a href="/files/project/{{ file.name }}?download=1" class="btn btn-sm btn-primary" title="Herunterladen" download>↓</a>
+              {% endif %}
               <a href="/files/project/delete/{{ file.name }}" class="btn btn-sm btn-danger"
                 onclick="return confirm('Projektdokument löschen?')" title="Löschen">✕</a>
             </div>
@@ -170,7 +173,11 @@
           <div class="file-actions">
             <button class="btn btn-sm btn-secondary"
               onclick="viewAgentFile(event, '{{ agent_key }}', '{{ file.name }}')" title="Anzeigen">👁</button>
+            {% if file.name.lower().endswith(('.md', '.txt', '.json', '.csv')) %}
+            <a href="/files/editor?type=agent&agent={{ agent_key|urlencode }}&name={{ file.name|urlencode }}" class="btn btn-sm btn-primary" title="Bearbeiten">✎</a>
+            {% else %}
             <a href="/files/agent/{{ agent_key }}/{{ file.name }}?download=1" class="btn btn-sm btn-primary" title="Herunterladen" download>↓</a>
+            {% endif %}
             <a href="/files/agent/{{ agent_key }}/delete/{{ file.name }}" class="btn btn-sm btn-danger"
               onclick="return confirm('Agent-Datei löschen?')" title="Löschen">✕</a>
           </div>
@@ -205,31 +212,11 @@
   </div>
 </div>
 
-<!-- Email Editor Modal -->
-<div class="modal fade" id="editModal" tabindex="-1">
-  <div class="modal-dialog modal-xl">
-    <div class="modal-content">
-      <div class="modal-header">
-        <h5 class="modal-title">✎ Bearbeiten: <span id="editModalFilename"></span></h5>
-        <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
-      </div>
-      <div class="modal-body">
-        <textarea id="editModalContent" class="inline-editor" spellcheck="false"></textarea>
-        <div id="editSaveStatus" style="font-size:.8rem;color:var(--text-muted);margin-top:.5rem;height:1.2em;"></div>
-      </div>
-      <div class="modal-footer">
-        <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Abbrechen</button>
-        <button type="button" class="btn btn-primary" onclick="saveEmailFile()">💾 Speichern</button>
-      </div>
-    </div>
-  </div>
-</div>
+
 {% endblock %}
 
 {% block scripts %}
 <script>
-let currentEditFile = null;
-
 function openFileModal(title, url) {
   document.getElementById('fileModalTitle').textContent = title;
   const content = document.getElementById('fileModalContent');
@@ -257,48 +244,5 @@ function viewAgentFile(event, agentKey, name) {
   openFileModal(`${agentKey}/${name}`, `/files/agent/${agentKey}/view/${encodeURIComponent(name)}?json=1`);
 }
 
-function editEmailFile(name) {
-  currentEditFile = name;
-  document.getElementById('editModalFilename').textContent = name;
-  const textarea = document.getElementById('editModalContent');
-  const status = document.getElementById('editSaveStatus');
-  textarea.value = 'Wird geladen…';
-  status.textContent = '';
-  const modal = new bootstrap.Modal(document.getElementById('editModal'));
-  modal.show();
-  fetch('/files/email/view/' + encodeURIComponent(name) + '?json=1')
-    .then(r => r.json())
-    .then(d => { textarea.value = d.content || d.error || ''; })
-    .catch(e => { textarea.value = 'Fehler: ' + e.message; });
-}
-
-function saveEmailFile() {
-  if (!currentEditFile) return;
-  const content = document.getElementById('editModalContent').value;
-  const status = document.getElementById('editSaveStatus');
-  status.style.color = 'var(--text-muted)';
-  status.textContent = 'Speichern…';
-
-  fetch('/files/email/save/' + encodeURIComponent(currentEditFile), {
-    method: 'POST',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ content })
-  })
-  .then(r => r.json())
-  .then(d => {
-    if (d.ok) {
-      status.style.color = 'var(--success)';
-      status.textContent = '✓ Gespeichert';
-      setTimeout(() => { status.textContent = ''; }, 3000);
-    } else {
-      status.style.color = 'var(--danger)';
-      status.textContent = '✗ Fehler: ' + (d.error || 'Unbekannt');
-    }
-  })
-  .catch(e => {
-    status.style.color = 'var(--danger)';
-    status.textContent = '✗ ' + e.message;
-  });
-}
 </script>
 {% endblock %}