diff --git a/public/app.js b/public/app.js
index 9ddcced..5e28f2f 100755
--- a/public/app.js
+++ b/public/app.js
@@ -1,195 +1,246 @@
+/* ============================================================
+   Self-Organizing Static Site Framework  v2.4  (Local Libs)
+   ============================================================ */
+
 let INDEX, CURRENT_PATH = null, PATH_TO_EL = new Map();
-const treeEl = document.getElementById("tree");
-const mdView = document.getElementById("mdView");
-const htmlView = document.getElementById("htmlView");
-const metaLine = document.getElementById("meta");
-const sortSel = document.getElementById("sort");
+
+const treeEl    = document.getElementById("tree");
+const mdView    = document.getElementById("mdView");
+const mdWarn    = document.getElementById("mdWarn");
+const htmlView  = document.getElementById("htmlView");
+const metaLine  = document.getElementById("meta");
+const sortSel   = document.getElementById("sort");
 const filterSel = document.getElementById("filter");
 const searchBox = document.getElementById("search");
-const prevBtn = document.getElementById("prev");
-const nextBtn = document.getElementById("next");
-const sidebar = document.querySelector(".sidebar");
+const prevBtn   = document.getElementById("prev");
+const nextBtn   = document.getElementById("next");
+const sidebar   = document.querySelector(".sidebar");
 const navToggle = document.getElementById("navToggle");
-const overlay = document.querySelector(".overlay");
+const overlay   = document.querySelector(".overlay");
 
+/* Sidebar toggle */
 navToggle.addEventListener("click", () => sidebar.classList.toggle("open"));
-overlay.addEventListener("click", () => sidebar.classList.remove("open"));
+overlay.addEventListener("click",  () => sidebar.classList.remove("open"));
 
+/* Load index */
 async function loadIndex() {
+  // No CDN race now; libs are local. Still, surface diagnostics:
+  if (!window.marked) console.warn("⚠️ marked.js not detected.");
+  if (!window.DOMPurify) console.warn("⚠️ DOMPurify not detected.");
+
   const res = await fetch("/index.json", { cache: "no-store" });
   INDEX = await res.json();
   populateFilters();
   rebuildTree();
-  window.addEventListener("popstate", () => { const hp = location.hash.startsWith("#=") ? location.hash.slice(2) : null; if (hp) openPath(hp); });
-  const init = location.hash.startsWith("#=") ? location.hash.slice(2) : INDEX.flat.sort((a, b) => b.mtime - a.mtime)[0]?.path;
+
+  window.addEventListener("popstate", () => {
+    const hp = location.hash.startsWith("#=") ? location.hash.slice(2) : null;
+    if (hp) openPath(hp);
+  });
+
+  const init = location.hash.startsWith("#=")
+    ? location.hash.slice(2)
+    : INDEX.flat.sort((a,b)=>b.mtime-a.mtime)[0]?.path;
+
   openPath(init);
 }
+
 function populateFilters() {
   filterSel.innerHTML = '<option value="all">All</option>';
   for (const cat of INDEX.sections) {
-    const opt = document.createElement("option");
-    opt.value = opt.textContent = cat;
-    filterSel.appendChild(opt);
+    const o = document.createElement("option");
+    o.value = o.textContent = cat;
+    filterSel.appendChild(o);
   }
 }
+
 function rebuildTree() {
   treeEl.innerHTML = "";
   PATH_TO_EL.clear();
   const filter = filterSel.value;
-  const sort = sortSel.value;
-  const query = searchBox.value.trim().toLowerCase();
-  const root = { type: "dir", children: INDEX.tree };
-  const pruned = filterTree(root, f => (filter === "all" || f.path.split("/")[0] === filter) && (!query || (f.title || f.name).toLowerCase().includes(query)));
+  const sort   = sortSel.value;
+  const query  = searchBox.value.trim().toLowerCase();
+  const root   = { type: "dir", children: INDEX.tree };
+  const pruned = filterTree(root, f =>
+    (filter==="all" || f.path.split("/")[0]===filter) &&
+    (!query || (f.title||f.name).toLowerCase().includes(query))
+  );
   sortDir(pruned, sort);
   for (const c of pruned.children) treeEl.appendChild(renderNode(c));
   treeEl.querySelectorAll(".dir").forEach(d => d.classList.add("open"));
 }
+
 function filterTree(node, keep) {
   if (node.type === "file") return keep(node) ? node : null;
-  const kids = node.children.map(c => filterTree(c, keep)).filter(Boolean);
-  return kids.length ? { ...node, children: kids } : null;
+  const kids = node.children.map(c=>filterTree(c,keep)).filter(Boolean);
+  return kids.length ? {...node, children:kids} : null;
 }
 function sortDir(node, sort) {
-  const cmp = sort === "name" ? (a, b) => a.name.localeCompare(b.name) :
-              sort === "old" ? (a, b) => a.mtime - b.mtime : (a, b) => b.mtime - a.mtime;
-  node.children.sort((a, b) => (a.type === "dir" && b.type !== "dir") ? -1 : (a.type !== "dir" && b.type === "dir") ? 1 : cmp(a, b));
-  node.children.forEach(c => c.type === "dir" && sortDir(c, sort));
+  const cmp = sort==="name" ? (a,b)=>a.name.localeCompare(b.name)
+            : sort==="old" ? (a,b)=>a.mtime-b.mtime
+            : (a,b)=>b.mtime-a.mtime;
+  node.children.sort((a,b)=>
+    (a.type==="dir"&&b.type!=="dir")?-1:
+    (a.type!=="dir"&&b.type==="dir")?1:cmp(a,b));
+  node.children.forEach(c=>c.type==="dir"&&sortDir(c,sort));
 }
-function renderNode(node) {
-  if (node.type === "dir") {
-    const div = document.createElement("div");
-    div.className = "dir";
-    div.setAttribute("aria-expanded", "false");
-    const lbl = document.createElement("span");
-    lbl.className = "label";
-    lbl.textContent = node.name || "/";
-    lbl.addEventListener("click", () => {
-      const idx = node.children.find(c => c.type === "file" && /^index\.(md|html)$/i.test(c.name));
-      if (idx) openPath(idx.path);
-      else div.classList.toggle("open");
+function renderNode(n) {
+  if (n.type==="dir") {
+    const d = document.createElement("div");
+    d.className="dir"; d.setAttribute("aria-expanded","false");
+    const lbl=document.createElement("span");
+    lbl.className="label"; lbl.textContent=n.name||"/";
+    lbl.addEventListener("click",()=>{
+      const idx=n.children.find(c=>c.type==="file"&&/^index\.(md|html)$/i.test(c.name));
+      if(idx) openPath(idx.path); else d.classList.toggle("open");
     });
-    div.appendChild(lbl);
-    const kids = document.createElement("div");
-    kids.className = "children";
-    node.children.forEach(c => kids.appendChild(renderNode(c)));
-    div.appendChild(kids);
-    return div;
+    d.appendChild(lbl);
+    const kids=document.createElement("div");
+    kids.className="children";
+    n.children.forEach(c=>kids.appendChild(renderNode(c)));
+    d.appendChild(kids);
+    return d;
   }
-  const a = document.createElement("a");
-  a.className = "file";
-  a.innerHTML = `${node.pinned ? '<span class="pin">📌</span>' : ''}${iconForExt(node.ext)} ${node.title} <span class="meta">(${fmtDate(node.mtime)} · ${node.name})</span>`;
-  a.addEventListener("click", e => { e.preventDefault(); openPath(node.path); });
-  PATH_TO_EL.set(node.path, a);
+  const a=document.createElement("a");
+  a.className="file";
+  a.innerHTML=`${n.pinned?'📌 ':''}${iconForExt(n.ext)} ${n.title}
+               <span class="meta">(${fmtDate(n.mtime)} · ${n.name})</span>`;
+  a.addEventListener("click",e=>{e.preventDefault();openPath(n.path);});
+  PATH_TO_EL.set(n.path,a);
   return a;
 }
-function iconForExt(ext) { return ext === ".md" ? "📝" : "🧩"; }
-function fmtDate(ms) { return new Date(ms).toISOString().slice(0, 10); }
-function findDir(path) {
-  path = path.replace(/\/$/, '');
-  function search(node) {
-    if (node.type === "dir" && node.path === path) return node;
-    for (const c of node.children || []) {
-      const found = search(c);
-      if (found) return found;
-    }
+function iconForExt(ext){return ext===".md"?"📝":"🧩";}
+function fmtDate(ms){return new Date(ms).toISOString().slice(0,10);}
+
+function findDir(p){
+  p=p.replace(/\/$/,'');
+  function search(n){
+    if(n.type==="dir"&&n.path===p) return n;
+    for(const c of n.children||[]){const f=search(c);if(f)return f;}
   }
-  return search({ children: INDEX.tree });
+  return search({children:INDEX.tree});
 }
-async function openPath(path) {
-  if (path === CURRENT_PATH) return;
-  CURRENT_PATH = path;
-  if (location.hash !== `#=${path}`) history.pushState(null, "", `#=${path}`);
-  let f = INDEX.flat.find(x => x.path === path);
-  if (!f) {
-    const dir = findDir(path);
-    if (dir) {
-      const idx = dir.children.find(c => c.type === "file" && /^index\.(md|html)$/i.test(c.name));
-      if (idx) return openPath(idx.path);
+
+async function openPath(path){
+  if(path===CURRENT_PATH) return;
+  CURRENT_PATH=path;
+  if(location.hash!==`#=${path}`) history.pushState(null,"",`#=${path}`);
+
+  let f=INDEX.flat.find(x=>x.path===path);
+  if(!f){
+    const dir=findDir(path);
+    if(dir){
+      const idx=dir.children.find(c=>c.type==="file"&&/^index\.(md|html)$/i.test(c.name));
+      if(idx) return openPath(idx.path);
     }
-    metaLine.textContent = "Path not found: " + path;
+    metaLine.textContent="Path not found: "+path;
     return;
   }
-  metaLine.textContent = `${f.pinned ? "📌 " : ""}${fmtDate(f.mtime)} • ${f.name}`;
-  if (f.ext === ".md") await renderMarkdown(f.path);
+
+  metaLine.textContent=`${f.pinned?"📌 ":""}${fmtDate(f.mtime)} • ${f.name}`;
+
+  if(f.ext===".md") await renderMarkdown(f.path);
   else renderHTML(f.path);
+
   setActive(path);
   updatePager();
-  if (window.innerWidth < 900) sidebar.classList.remove("open");
+  if(window.innerWidth<900) sidebar.classList.remove("open");
 }
-async function renderMarkdown(path) {
-  mdView.innerHTML = "<p style='color:var(--muted);font-style:italic;'>Loading…</p>";
-  mdView.style.display = "block";
-  htmlView.style.display = "none";
-  try {
-    const res = await fetch("/" + path);
-    if (!res.ok) throw new Error("File not found: " + path);
-    const text = await res.text();
-    let html = text.replace(/&/g, '&amp;').replace(/</g, '&lt;');
-    let usedFallback = true;
+
+/* ---------- Markdown (robust) ---------- */
+async function renderMarkdown(path){
+  mdWarn.style.display = "none";
+  mdView.innerHTML="<p class='loading-note'>Loading…</p>";
+  htmlView.style.display="none";
+  mdView.style.display="block";
+
+  try{
+    const res=await fetch("/"+path, { cache: "no-store" });
+    if(!res.ok) throw new Error("File not found: "+path);
+    const text=await res.text();
+
+    let usedFallback = false;
+    let html;
+
     if (window.marked) {
       html = window.marked.parse(text);
-      usedFallback = false;
+    } else {
+      // explicit, visible signal
+      usedFallback = true;
+      html = text.replace(/&/g,"&amp;").replace(/</g,"&lt;");
     }
-    let safe = html;
-    if (window.DOMPurify) safe = window.DOMPurify.sanitize(html);
-    requestAnimationFrame(() => {
+
+    const safe = window.DOMPurify ? window.DOMPurify.sanitize(html) : html;
+
+    requestAnimationFrame(()=>{
       mdView.innerHTML = safe;
       mdView.scrollTop = 0;
       mdView.classList.add("fade-in");
+      mdView.style.display = "block";
+      if (usedFallback) mdWarn.style.display = "block";
     });
-    if (usedFallback) console.warn("Markdown rendered as plain text: marked.js not loaded. Check CDN or vendor locally.");
-  } catch (e) {
-    mdView.innerHTML = `<p style='color:red;'>${e.message}</p>`;
+
+  }catch(e){
+    mdView.innerHTML=`<p style='color:red;'>${e.message}</p>`;
   }
 }
-function renderHTML(path) {
-  htmlView.style.display = "none";
-  mdView.style.display = "none";
-  metaLine.innerHTML += " <span style='color:var(--muted);'>Loading…</span>";
-  htmlView.src = "/" + path;
-  htmlView.onload = () => {
-    htmlView.style.display = "block";
-    htmlView.classList.add("fade-in");
-    metaLine.innerHTML = metaLine.innerHTML.replace(" Loading…", "");
-  };
-  htmlView.onerror = () => metaLine.innerHTML += " <span style='color:red;'>Load failed.</span>";
+
+/* ---------- HTML ---------- */
+function renderHTML(path){
+  htmlView.src="/"+path;
+  htmlView.style.display="block";
+  mdView.style.display="none";
 }
-function setActive(path) {
-  document.querySelectorAll(".file.active").forEach(el => el.classList.remove("active"));
-  const el = PATH_TO_EL.get(path);
-  if (el) {
+
+/* ---------- Active + Pager ---------- */
+function setActive(path){
+  document.querySelectorAll(".file.active").forEach(el=>el.classList.remove("active"));
+  const el=PATH_TO_EL.get(path);
+  if(el){
     el.classList.add("active");
-    let p = el.parentElement;
-    while (p && p !== treeEl) {
-      if (p.classList.contains("children")) p.parentElement.classList.add("open");
-      p = p.parentElement;
+    let p=el.parentElement;
+    while(p&&p!==treeEl){
+      if(p.classList.contains("children")) p.parentElement.classList.add("open");
+      p=p.parentElement;
     }
   }
 }
-function updatePager() {
-  const query = searchBox.value.trim().toLowerCase();
-  const list = INDEX.flat.filter(f => (filterSel.value === "all" || f.path.split("/")[0] === filterSel.value) && (!query || f.title.toLowerCase().includes(query)));
-  const cmp = sortSel.value === "name" ? (a, b) => a.name.localeCompare(b.name) :
-              sortSel.value === "old" ? (a, b) => a.mtime - b.mtime : (a, b) => b.mtime - a.mtime;
+function updatePager(){
+  const q=searchBox.value.trim().toLowerCase();
+  const list=INDEX.flat.filter(f=>
+    (filterSel.value==="all"||f.path.split("/")[0]===filterSel.value)&&
+    (!q||f.title.toLowerCase().includes(q))
+  );
+  const cmp=sortSel.value==="name"?(a,b)=>a.name.localeCompare(b.name)
+            :sortSel.value==="old"?(a,b)=>a.mtime-b.mtime
+            :(a,b)=>b.mtime-a.mtime;
   list.sort(cmp);
-  const i = list.findIndex(x => x.path === CURRENT_PATH);
-  prevBtn.disabled = i <= 0;
-  nextBtn.disabled = i >= list.length - 1 || i < 0;
-  prevBtn.onclick = () => i > 0 && openPath(list[i - 1].path);
-  nextBtn.onclick = () => i < list.length - 1 && openPath(list[i + 1].path);
+  const i=list.findIndex(x=>x.path===CURRENT_PATH);
+  prevBtn.disabled=i<=0;
+  nextBtn.disabled=i>=list.length-1||i<0;
+  prevBtn.onclick=()=>i>0&&openPath(list[i-1].path);
+  nextBtn.onclick=()=>i<list.length-1&&openPath(list[i+1].path);
 }
+
+/* Controls */
 let searchTimer;
-searchBox.addEventListener("input", () => { clearTimeout(searchTimer); searchTimer = setTimeout(rebuildTree, 300); });
-sortSel.addEventListener("change", rebuildTree);
-filterSel.addEventListener("change", rebuildTree);
-document.body.addEventListener("click", e => {
-  const a = e.target.closest("a[href]");
-  if (!a) return;
-  const href = a.getAttribute("href");
-  if (href.startsWith("/") && !href.startsWith("//") && !a.target) {
+searchBox.addEventListener("input",()=>{
+  clearTimeout(searchTimer);
+  searchTimer=setTimeout(rebuildTree,300);
+});
+sortSel.addEventListener("change",rebuildTree);
+filterSel.addEventListener("change",rebuildTree);
+
+/* Internal link interception */
+document.body.addEventListener("click",e=>{
+  const a=e.target.closest("a[href]");
+  if(!a) return;
+  const href=a.getAttribute("href");
+  if(href.startsWith("/")&&!href.startsWith("//")&&!a.target){
     e.preventDefault();
-    openPath(href.replace(/^\//, ""));
+    openPath(href.replace(/^\//,""));
   }
 });
-window.addEventListener("resize", () => { if (window.innerWidth < 900) sidebar.classList.remove("open"); });
-window.addEventListener("DOMContentLoaded", loadIndex);
\ No newline at end of file
+
+window.addEventListener("resize",()=>{ if(window.innerWidth<900) sidebar.classList.remove("open"); });
+window.addEventListener("DOMContentLoaded",loadIndex);
\ No newline at end of file