diff --git a/simple-merge-template/index.html b/simple-merge-template/index.html
new file mode 100644
index 0000000..3f05910
--- /dev/null
+++ b/simple-merge-template/index.html
@@ -0,0 +1,422 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="UTF-8">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<title>Template Merge</title>
+<style>
+  * { box-sizing: border-box; margin: 0; padding: 0; }
+  body { font-family: system-ui, sans-serif; background: #f5f5f5; color: #333; padding: 2rem; }
+  h1 { margin-bottom: 1.5rem; }
+  .container { max-width: 900px; margin: 0 auto; display: flex; flex-direction: column; gap: 1.5rem; }
+  label { font-weight: 600; display: block; margin-bottom: 0.3rem; }
+  textarea { width: 100%; min-height: 120px; font-family: monospace; font-size: 0.95rem; padding: 0.5rem; border: 1px solid #ccc; border-radius: 4px; resize: vertical; }
+  .data-section { border: 1px solid #ccc; border-radius: 4px; padding: 0.75rem; background: #fff; }
+  .data-row { display: flex; gap: 0.5rem; margin-bottom: 0.5rem; align-items: center; }
+  .data-row input { flex: 1; font-family: monospace; font-size: 0.9rem; padding: 0.35rem 0.5rem; border: 1px solid #ccc; border-radius: 4px; }
+  .data-row .remove-btn { background: #e55; color: #fff; border: none; border-radius: 4px; padding: 0.35rem 0.6rem; cursor: pointer; }
+  .btn-row { display: flex; gap: 0.5rem; margin-top: 0.5rem; }
+  button { padding: 0.5rem 1rem; border: none; border-radius: 4px; cursor: pointer; font-size: 0.9rem; }
+  .add-btn { background: #4a9; color: #fff; }
+  .merge-btn { background: #36c; color: #fff; font-size: 1rem; padding: 0.7rem 1.5rem; }
+  .clear-btn { background: #aaa; color: #fff; }
+  .clear-btn:disabled, #copy-btn:disabled, #tpl-clear-btn:disabled { opacity: 0.4; cursor: not-allowed; }
+  #output { width: 100%; min-height: 150px; font-family: monospace; font-size: 0.95rem; padding: 0.5rem; border: 1px solid #ccc; border-radius: 4px; background: #fff; white-space: pre-wrap; }
+  .hint { font-size: 0.8rem; color: #888; margin-top: 0.2rem; }
+  .error { color: #c33; font-size: 0.85rem; margin-top: 0.3rem; }
+</style>
+</head>
+<body>
+<div class="container">
+  <h1>Template Merge</h1>
+
+  <div>
+    <label for="template">Template</label>
+    <div style="position:relative;">
+      <textarea id="template" placeholder="Hello {{name}}, you have {{count}} messages.&#10;Items:&#10;{{#items}}- {{value}}&#10;{{/items}}"></textarea>
+      <button class="add-btn" onclick="pasteTemplate()" id="paste-btn" style="position:absolute;top:0.5rem;right:0.5rem;padding:0.35rem 0.6rem;">Paste</button>
+      <button class="clear-btn" onclick="clearTemplate()" id="tpl-clear-btn" style="position:absolute;top:0.5rem;right:4.7rem;padding:0.35rem 0.6rem;">Clear</button>
+    </div>
+    <div class="hint">Use <code>{{key}}</code> for variables, <code>{{#list}}...{{/list}}</code> for loop blocks. Use <code>{{value}}</code> when data is a simple string.</div>
+  </div>
+
+  <div class="data-section">
+    <label>Data List</label>
+    <div id="data-list"></div>
+    <div class="btn-row">
+      <button class="add-btn" onclick="addDataItem('')">+ String</button>
+      <button class="add-btn" onclick="addDataItem('{}')">+ JSON</button>
+      <button class="clear-btn" onclick="clearData()">Clear All</button>
+      <button class="add-btn" onclick="showJsonlImport()">Import JSONL</button>
+      <button class="add-btn" onclick="showTextImport()">Import Lines</button>
+    </div>
+    <div id="jsonl-panel" style="display:none; margin-top:0.5rem;">
+      <textarea id="jsonl-input" placeholder='{"key":"value"}\n{"key2":"value2"}' style="min-height:80px;"></textarea>
+      <div class="btn-row">
+        <button class="merge-btn" onclick="importJsonl()">Import</button>
+        <button class="clear-btn" onclick="hideJsonlImport()">Cancel</button>
+      </div>
+      <div id="jsonl-error" class="error"></div>
+    </div>
+    <div id="text-panel" style="display:none; margin-top:0.5rem;">
+      <textarea id="text-input" placeholder="line1&#10;line2&#10;line3" style="min-height:80px;"></textarea>
+      <div class="btn-row">
+        <button class="merge-btn" onclick="importLines()">Import</button>
+        <button class="clear-btn" onclick="hideTextImport()">Cancel</button>
+      </div>
+    </div>
+  </div>
+
+  <button class="merge-btn" onclick="merge()">Merge</button>
+
+  <div>
+    <label for="output">Output</label>
+    <div id="error" class="error"></div>
+    <div style="position:relative;">
+      <div id="output" readonly></div>
+      <button class="add-btn" onclick="copyOutput()" id="copy-btn" style="position:absolute;top:0.5rem;right:0.5rem;padding:0.35rem 0.6rem;" disabled>Copy</button>
+    </div>
+  </div>
+</div>
+
+<script>
+let dataItems = [];
+let itemIdCounter = 0;
+
+// --- LocalStorage ---
+
+function saveState() {
+  localStorage.setItem('template', document.getElementById('template').value);
+  localStorage.setItem('dataItems', JSON.stringify(dataItems));
+}
+
+function loadState() {
+  const tpl = localStorage.getItem('template');
+  if (tpl != null) document.getElementById('template').value = tpl;
+  const items = localStorage.getItem('dataItems');
+  if (items != null) {
+    try {
+      dataItems = JSON.parse(items);
+      itemIdCounter = dataItems.reduce((max, d) => Math.max(max, d.id), 0) + 1;
+    } catch {}
+  }
+}
+
+function addDataItem(value) {
+  const id = itemIdCounter++;
+  dataItems.push({ id, value });
+  renderDataList();
+  saveState();
+}
+
+function removeDataItem(id) {
+  dataItems = dataItems.filter(d => d.id !== id);
+  renderDataList();
+  saveState();
+}
+
+function updateDataItem(id, value) {
+  const item = dataItems.find(d => d.id === id);
+  if (item) item.value = value;
+  saveState();
+}
+
+function clearData() {
+  dataItems = [];
+  renderDataList();
+  saveState();
+}
+
+function showJsonlImport() {
+  document.getElementById('jsonl-panel').style.display = 'block';
+  document.getElementById('jsonl-error').textContent = '';
+}
+
+function hideJsonlImport() {
+  document.getElementById('jsonl-panel').style.display = 'none';
+  document.getElementById('jsonl-input').value = '';
+}
+
+function showTextImport() {
+  document.getElementById('text-panel').style.display = 'block';
+}
+
+function hideTextImport() {
+  document.getElementById('text-panel').style.display = 'none';
+  document.getElementById('text-input').value = '';
+}
+
+function importLines() {
+  const raw = document.getElementById('text-input').value.trim();
+  if (!raw) return;
+  raw.split(/\n/).filter(l => l.trim()).forEach(line => addDataItem(line.trim()));
+  hideTextImport();
+}
+
+function importJsonl() {
+  const raw = document.getElementById('jsonl-input').value.trim();
+  const errorEl = document.getElementById('jsonl-error');
+  errorEl.textContent = '';
+  if (!raw) { errorEl.textContent = 'Input is empty.'; return; }
+  const lines = raw.split(/\n/).filter(l => l.trim());
+  for (const line of lines) {
+    try {
+      JSON.parse(line.trim());
+    } catch {
+      errorEl.textContent = 'Invalid JSON line: ' + line.trim().slice(0, 60);
+      return;
+    }
+    addDataItem(line.trim());
+  }
+  hideJsonlImport();
+}
+
+function renderDataList() {
+  const container = document.getElementById('data-list');
+  container.innerHTML = '';
+  dataItems.forEach(item => {
+    const row = document.createElement('div');
+    row.className = 'data-row';
+    const isJson = item.value.trim().startsWith('{');
+    const placeholder = isJson ? '{"key": "value"}' : 'simple text value';
+    row.innerHTML = `<input value="${escapeHtml(item.value)}" placeholder="${placeholder}" oninput="updateDataItem(${item.id}, this.value)"><button class="remove-btn" onclick="removeDataItem(${item.id})">x</button>`;
+    container.appendChild(row);
+  });
+  document.querySelector('.clear-btn').disabled = dataItems.length === 0;
+}
+
+function escapeHtml(s) {
+  return s.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/"/g,'&quot;');
+}
+
+function copyOutput() {
+  const text = document.getElementById('output').textContent;
+  if (!text) return;
+  navigator.clipboard.writeText(text).then(() => {
+    const btn = document.getElementById('copy-btn');
+    btn.textContent = 'Copied!';
+    setTimeout(() => { btn.textContent = 'Copy'; }, 1500);
+  });
+}
+
+function pasteTemplate() {
+  navigator.clipboard.readText().then(text => {
+    document.getElementById('template').value = text;
+    updateTemplateButtons();
+    saveState();
+  });
+}
+
+let undoTimeout = null;
+let undoContent = null;
+let undoCountdown = null;
+
+function clearTemplate() {
+  const tpl = document.getElementById('template').value;
+  if (!tpl) return;
+  undoContent = tpl;
+  document.getElementById('template').value = '';
+
+  const btn = document.getElementById('tpl-clear-btn');
+  btn.textContent = 'Undo (10)';
+  btn.onclick = restoreTemplate;
+
+  updateTemplateButtons();
+  saveState();
+
+  let seconds = 10;
+  if (undoTimeout) clearTimeout(undoTimeout);
+  if (undoCountdown) clearInterval(undoCountdown);
+  undoCountdown = setInterval(() => {
+    seconds--;
+    if (seconds <= 0) {
+      clearInterval(undoCountdown);
+      return;
+    }
+    btn.textContent = `Undo (${seconds})`;
+  }, 1000);
+
+  undoTimeout = setTimeout(() => {
+    clearInterval(undoCountdown);
+    btn.textContent = 'Clear';
+    btn.onclick = clearTemplate;
+    undoContent = null;
+    updateTemplateButtons();
+  }, 10000);
+}
+
+function restoreTemplate() {
+  if (undoContent == null) return;
+  document.getElementById('template').value = undoContent;
+  updateTemplateButtons();
+  saveState();
+  undoContent = null;
+
+  const btn = document.getElementById('tpl-clear-btn');
+  btn.textContent = 'Clear';
+  btn.onclick = clearTemplate;
+  if (undoTimeout) { clearTimeout(undoTimeout); undoTimeout = null; }
+  if (undoCountdown) { clearInterval(undoCountdown); undoCountdown = null; }
+}
+
+function updateTemplateButtons() {
+  const tpl = document.getElementById('template').value;
+  const btn = document.getElementById('tpl-clear-btn');
+  if (btn.textContent.startsWith('Undo')) {
+    btn.disabled = false;
+  } else {
+    btn.disabled = !tpl;
+  }
+}
+
+// --- AST Parser ---
+
+function parseTemplate(template) {
+  const tokens = tokenize(template);
+  return buildAst(tokens);
+}
+
+function tokenize(template) {
+  const tokens = [];
+  let i = 0;
+  while (i < template.length) {
+    const openIdx = template.indexOf('{{', i);
+    if (openIdx === -1) {
+      if (i < template.length) tokens.push({ type: 'text', value: template.slice(i) });
+      break;
+    }
+    if (openIdx > i) tokens.push({ type: 'text', value: template.slice(i, openIdx) });
+    const closeIdx = template.indexOf('}}', openIdx + 2);
+    if (closeIdx === -1) {
+      tokens.push({ type: 'text', value: template.slice(openIdx) });
+      break;
+    }
+    const inner = template.slice(openIdx + 2, closeIdx).trim();
+    if (inner.startsWith('#')) {
+      tokens.push({ type: 'open', key: inner.slice(1).trim() });
+    } else if (inner.startsWith('/')) {
+      tokens.push({ type: 'close', key: inner.slice(1).trim() });
+    } else {
+      // Split on first ':' for default value: {{key:default}}
+      const colonIdx = inner.indexOf(':');
+      if (colonIdx > 0) {
+        tokens.push({ type: 'var', key: inner.slice(0, colonIdx), default: inner.slice(colonIdx + 1) });
+      } else {
+        tokens.push({ type: 'var', key: inner });
+      }
+    }
+    i = closeIdx + 2;
+  }
+  return tokens;
+}
+
+function buildAst(tokens) {
+  const ast = [];
+  let pos = 0;
+  function parseBlock(endType) {
+    const nodes = [];
+    while (pos < tokens.length) {
+      const tok = tokens[pos];
+      if (tok.type === endType) { pos++; return nodes; }
+      if (tok.type === 'text') { nodes.push({ type: 'text', value: tok.value }); pos++; continue; }
+      if (tok.type === 'var') { nodes.push({ type: 'var', key: tok.key, default: tok.default }); pos++; continue; }
+      if (tok.type === 'open') {
+        const key = tok.key;
+        pos++;
+        const children = parseBlock('close');
+        // verify matching key
+        nodes.push({ type: 'block', key, children });
+        continue;
+      }
+      pos++;
+    }
+    return nodes;
+  }
+  return parseBlock(null);
+}
+
+// --- Resolve helper ---
+
+function resolvePath(ctx, keyPath) {
+  const parts = keyPath.split('.');
+  let obj = ctx;
+  for (const p of parts) {
+    if (obj == null || typeof obj !== 'object') return undefined;
+    obj = obj[p];
+  }
+  return obj;
+}
+
+// --- Render AST ---
+
+function renderAst(ast, ctx) {
+  let result = '';
+  for (const node of ast) {
+    if (node.type === 'text') { result += node.value; }
+    else if (node.type === 'var') {
+      const val = resolvePath(ctx, node.key);
+      if (val != null) { result += String(val); }
+      else if (node.default !== undefined) { result += node.default; }
+    }
+    else if (node.type === 'block') {
+      const arr = resolvePath(ctx, node.key);
+      if (Array.isArray(arr)) {
+        for (const item of arr) {
+          result += renderAst(node.children, item);
+        }
+      }
+    }
+  }
+  return result;
+}
+
+// --- Merge action ---
+
+function merge() {
+  const errorEl = document.getElementById('error');
+  const outputEl = document.getElementById('output');
+  errorEl.textContent = '';
+  outputEl.textContent = '';
+
+  const template = document.getElementById('template').value;
+  if (!template.trim()) { errorEl.textContent = 'Template is empty.'; return; }
+
+  let ast;
+  try {
+    ast = parseTemplate(template);
+  } catch (e) {
+    errorEl.textContent = 'Template parse error: ' + e.message;
+    return;
+  }
+
+  // Render template once per data item, concatenate results
+  const results = dataItems
+    .filter(item => item.value.trim())
+    .map(item => {
+      const trimmed = item.value.trim();
+      let ctx;
+      if (trimmed.startsWith('{')) {
+        try {
+          ctx = JSON.parse(trimmed);
+        } catch {
+          ctx = { value: trimmed };
+        }
+      } else {
+        ctx = { value: trimmed };
+      }
+      return renderAst(ast, ctx);
+    });
+
+  outputEl.textContent = results.join('\n');
+  document.getElementById('copy-btn').disabled = results.length === 0 || results.join('') === '';
+}
+
+// Init
+document.getElementById('template').addEventListener('input', () => { saveState(); updateTemplateButtons(); });
+loadState();
+renderDataList();
+updateTemplateButtons();
+if (dataItems.length === 0) addDataItem('');
+</script>
+</body>
+</html>
diff --git a/simple-merge-template/site.json b/simple-merge-template/site.json
new file mode 100644
index 0000000..d16f378
--- /dev/null
+++ b/simple-merge-template/site.json
@@ -0,0 +1,3 @@
+{
+    "path":"simple-merge-template"
+}
