diff --git a/admin_ui/index.html b/admin_ui/index.html
new file mode 100644
index 0000000..ce724d5
--- /dev/null
+++ b/admin_ui/index.html
@@ -0,0 +1,252 @@
+<!doctype html>
+<html lang="de">
+<head>
+  <meta charset="utf-8" />
+  <title>Club Builder Admin</title>
+  <meta name="viewport" content="width=device-width, initial-scale=1" />
+  <style>
+    body {
+      margin: 0;
+      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
+      background: #111827;
+      color: #e5e7eb;
+      display: flex;
+      height: 100vh;
+      overflow: hidden;
+    }
+    .sidebar {
+      width: 220px;
+      border-right: 1px solid #1f2937;
+      background: #020617;
+      padding: 0.75rem;
+      box-sizing: border-box;
+      display: flex;
+      flex-direction: column;
+      gap: 0.5rem;
+    }
+    .sidebar h1 {
+      font-size: 1rem;
+      margin: 0 0 0.5rem 0;
+      color: #f9fafb;
+    }
+    .page-list {
+      list-style: none;
+      padding: 0;
+      margin: 0;
+      flex: 1;
+      overflow-y: auto;
+    }
+    .page-list li {
+      margin-bottom: 0.25rem;
+    }
+    .page-btn {
+      width: 100%;
+      text-align: left;
+      background: #0f172a;
+      color: #e5e7eb;
+      border: 1px solid transparent;
+      border-radius: 0.4rem;
+      padding: 0.35rem 0.5rem;
+      font-size: 0.85rem;
+      cursor: pointer;
+    }
+    .page-btn.active {
+      background: #111827;
+      border-color: #4b5563;
+    }
+    .main {
+      flex: 1;
+      display: flex;
+      flex-direction: row;
+      min-width: 0;
+    }
+    .editor {
+      flex: 1;
+      display: flex;
+      flex-direction: column;
+      padding: 0.75rem;
+      box-sizing: border-box;
+      border-right: 1px solid #1f2937;
+      min-width: 0;
+    }
+    .editor-header {
+      display: flex;
+      align-items: center;
+      gap: 0.5rem;
+      margin-bottom: 0.5rem;
+    }
+    .editor-header span {
+      font-size: 0.9rem;
+      color: #9ca3af;
+    }
+    .editor textarea {
+      flex: 1;
+      width: 100%;
+      resize: none;
+      border-radius: 0.4rem;
+      border: 1px solid #374151;
+      background: #020617;
+      color: #e5e7eb;
+      padding: 0.5rem;
+      font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
+      font-size: 0.8rem;
+      box-sizing: border-box;
+    }
+    .editor button {
+      padding: 0.25rem 0.7rem;
+      border-radius: 999px;
+      border: none;
+      cursor: pointer;
+      font-size: 0.8rem;
+    }
+    .btn-primary {
+      background: #10b981;
+      color: #022c22;
+    }
+    .btn-primary:disabled {
+      opacity: 0.5;
+      cursor: default;
+    }
+    .status {
+      font-size: 0.75rem;
+      color: #9ca3af;
+      margin-left: auto;
+    }
+    .preview {
+      width: 45%;
+      min-width: 320px;
+      display: flex;
+      flex-direction: column;
+      box-sizing: border-box;
+    }
+    .preview-header {
+      padding: 0.5rem 0.75rem;
+      border-bottom: 1px solid #1f2937;
+      font-size: 0.85rem;
+      color: #9ca3af;
+      background: #020617;
+    }
+    .preview iframe {
+      flex: 1;
+      width: 100%;
+      border: none;
+      background: #000;
+    }
+  </style>
+</head>
+<body>
+  <aside class="sidebar">
+    <h1>Pages</h1>
+    <ul class="page-list" id="page-list"></ul>
+  </aside>
+
+  <main class="main">
+    <section class="editor">
+      <div class="editor-header">
+        <span id="editor-title">No page selected</span>
+        <button class="btn-primary" id="save-btn" disabled>Save</button>
+        <span class="status" id="status"></span>
+      </div>
+      <textarea id="json-editor" placeholder="Select a page from the left…"></textarea>
+    </section>
+    <section class="preview">
+      <div class="preview-header">
+        Preview: <span id="preview-label">–</span>
+      </div>
+      <iframe id="preview-frame" src="about:blank"></iframe>
+    </section>
+  </main>
+
+  <script>
+    // Same origin: /api/... and /preview/... on builder-preview.clubdaguerre.de
+    const API_BASE = '';
+
+    const pageListEl = document.getElementById('page-list');
+    const editorTitleEl = document.getElementById('editor-title');
+    const previewLabelEl = document.getElementById('preview-label');
+    const previewFrameEl = document.getElementById('preview-frame');
+    const jsonEditorEl = document.getElementById('json-editor');
+    const saveBtnEl = document.getElementById('save-btn');
+    const statusEl = document.getElementById('status');
+
+    let currentSlug = null;
+
+    async function loadPages() {
+      const res = await fetch(API_BASE + '/api/pages');
+      const pages = await res.json();
+
+      pageListEl.innerHTML = '';
+      pages.forEach(page => {
+        const li = document.createElement('li');
+        const btn = document.createElement('button');
+        btn.className = 'page-btn';
+        btn.textContent = page.title || page.slug || '(untitled)';
+        btn.dataset.slug = page.slug;
+        btn.onclick = () => selectPage(page.slug, btn);
+        li.appendChild(btn);
+        pageListEl.appendChild(li);
+      });
+    }
+
+    async function selectPage(slug, buttonEl) {
+      currentSlug = slug;
+      statusEl.textContent = 'Loading…';
+      saveBtnEl.disabled = true;
+
+      document.querySelectorAll('.page-btn').forEach(b => b.classList.remove('active'));
+      if (buttonEl) buttonEl.classList.add('active');
+
+      const res = await fetch(API_BASE + '/api/pages/' + encodeURIComponent(slug));
+      const data = await res.json();
+
+      editorTitleEl.textContent = slug;
+      previewLabelEl.textContent = slug;
+      jsonEditorEl.value = JSON.stringify(data, null, 2);
+      saveBtnEl.disabled = false;
+      statusEl.textContent = 'Loaded';
+
+      previewFrameEl.src = API_BASE + '/preview/' + encodeURIComponent(slug) + '/';
+    }
+
+    async function saveCurrent() {
+      if (!currentSlug) return;
+      let parsed;
+      try {
+        parsed = JSON.parse(jsonEditorEl.value);
+      } catch (e) {
+        alert('JSON is invalid: ' + e.message);
+        return;
+      }
+      saveBtnEl.disabled = true;
+      statusEl.textContent = 'Saving…';
+      const res = await fetch(API_BASE + '/api/pages/' + encodeURIComponent(currentSlug), {
+        method: 'PUT',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(parsed),
+      });
+      if (!res.ok) {
+        statusEl.textContent = 'Error: ' + res.status;
+        saveBtnEl.disabled = false;
+        return;
+      }
+      statusEl.textContent = 'Saved';
+      saveBtnEl.disabled = false;
+
+      // refresh preview
+      previewFrameEl.src = API_BASE + '/preview/' + encodeURIComponent(currentSlug) + '/';
+    }
+
+    jsonEditorEl.addEventListener('input', () => {
+      if (!currentSlug) return;
+      statusEl.textContent = 'Changed (not saved)';
+    });
+
+    saveBtnEl.addEventListener('click', saveCurrent);
+
+    loadPages().catch(err => {
+      console.error(err);
+      statusEl.textContent = 'Error loading pages';
+    });
+  </script>
+</body>
+</html>
