diff --git a/public/app.js b/public/app.js
index d9854c4..5aaa285 100755
--- a/public/app.js
+++ b/public/app.js
@@ -1,3 +1,140 @@
+const els = {
+  menuBtn: document.getElementById("menuBtn"),
+  primaryNav: document.getElementById("primaryNav"),
+  sectionSelect: document.getElementById("sectionSelect"),
+  tagSelect: document.getElementById("tagSelect"),
+  sortSelect: document.getElementById("sortSelect"),
+  searchMode: document.getElementById("searchMode"),
+  searchBox: document.getElementById("searchBox"),
+  postList: document.getElementById("postList"),
+  viewer: document.getElementById("viewer"),
+  content: document.getElementById("content"),
+  toggleControls: document.getElementById("toggleControls"),
+  filterPanel: document.getElementById("filterPanel")
+};
+
+let indexData = null;
+let sidebarOpen = false;
+
+async function init() {
+  try {
+    indexData = await (await fetch("index.json")).json();
+    populateNav();
+    populateSections();
+    populateTags();
+    wireUI();
+    renderList();
+    handleHash();
+    window.addEventListener("hashchange", handleHash);
+  } catch (e) {
+    els.viewer.innerHTML = "<h1>Error</h1><p>Failed to load site data.</p>";
+  }
+}
+
+// TOP NAV: Only folder name if ANY index.* exists
+function populateNav() {
+  els.primaryNav.innerHTML = '<a href="#/">Home</a>';
+  const navSections = [...new Set(
+    indexData.flat
+      .filter(f => f.isIndex)
+      .map(f => f.path.split("/")[0])
+  )].sort();
+  navSections.forEach(s => {
+    els.primaryNav.innerHTML += `<a href="#/${s}/">${s.charAt(0).toUpperCase() + s.slice(1)}</a>`;
+  });
+}
+
+// DROPDOWN: Only sections with NON-index files
+function populateSections() {
+  els.sectionSelect.innerHTML = '<option value="all">All Sections</option>';
+  indexData.sections.forEach(s => {
+    const opt = document.createElement("option");
+    opt.value = s; opt.textContent = s;
+    els.sectionSelect.appendChild(opt);
+  });
+}
+
+function populateTags() {
+  indexData.tags.forEach(t => {
+    const opt = document.createElement("option");
+    opt.value = t; opt.textContent = t;
+    els.tagSelect.appendChild(opt);
+  });
+}
+
+function formatTimestamp(ms) {
+  const d = new Date(ms);
+  return `${d.getFullYear()}-${String(d.getMonth()+1).padStart(2,'0')}-${String(d.getDate()).padStart(2,'0')} ${String(d.getHours()).padStart(2,'0')}:${String(d.getMinutes()).padStart(2,'0')}`;
+}
+
+function wireUI() {
+  els.menuBtn.addEventListener("click", () => {
+    sidebarOpen = !sidebarOpen;
+    document.body.classList.toggle("sidebar-open", sidebarOpen);
+  });
+
+  els.toggleControls.addEventListener("click", () => {
+    const open = els.filterPanel.open;
+    els.filterPanel.open = !open;
+    els.toggleControls.textContent = open ? "Filters" : "Hide";
+  });
+
+  els.sectionSelect.addEventListener("change", () => {
+    renderList();
+    if (els.sectionSelect.value !== "all") loadDefaultForSection(els.sectionSelect.value);
+  });
+
+  [els.tagSelect, els.sortSelect, els.searchMode].forEach(el => el.addEventListener("change", renderList));
+  els.searchBox.addEventListener("input", renderList);
+
+  els.content.addEventListener("click", (e) => {
+    if (window.innerWidth < 1024 && document.body.classList.contains("sidebar-open")) {
+      if (!e.target.closest("#sidebar")) {
+        document.body.classList.remove("sidebar-open");
+        sidebarOpen = false;
+      }
+    }
+  });
+}
+
+function renderList() {
+  const section = els.sectionSelect.value;
+  const tags = Array.from(els.tagSelect.selectedOptions).map(o => o.value.toLowerCase());
+  const sort = els.sortSelect.value;
+  const mode = els.searchMode.value;
+  const query = els.searchBox.value.toLowerCase();
+
+  let posts = indexData.flat.filter(p => !p.isIndex);
+  if (section !== "all") posts = posts.filter(p => p.path.split('/')[0] === section);
+  if (tags.length) posts = posts.filter(p => tags.every(t => p.tags.includes(t)));
+  if (query) {
+    posts = posts.filter(p => {
+      const text = mode === "content" ? p.title + " " + p.excerpt : p.title;
+      return text.toLowerCase().includes(query);
+    });
+  }
+  posts.sort((a, b) => sort === "newest" ? b.mtime - a.mtime : a.mtime - b.mtime);
+
+  els.postList.innerHTML = posts.length ? "" : "<li>No posts found.</li>";
+  posts.forEach(p => {
+    const li = document.createElement("li");
+    const pin = p.isPinned ? "Star " : "";
+    const time = formatTimestamp(p.ctime);
+    li.innerHTML = `<a href="#/${p.path}">${pin}${p.title}</a><small>${time}</small>`;
+    els.postList.appendChild(li);
+  });
+}
+
+function loadDefaultForSection(section) {
+  const posts = indexData.flat.filter(p => p.path.split('/')[0] === section && !p.isIndex);
+  if (!posts.length) {
+    els.viewer.innerHTML = `<h1>${section}</h1><p>No content yet.</p>`;
+    return;
+  }
+  const pinned = posts.find(p => p.isPinned) || posts.sort((a,b) => b.mtime - a.mtime)[0];
+  location.hash = `#/${pinned.path}`;
+}
+
 async function handleHash() {
   els.viewer.innerHTML = "";
   const rel = location.hash.replace(/^#\//, "");
@@ -20,11 +157,9 @@ async function handleHash() {
           renderIframe(indexFile.path);
         }
       } catch (e) {
-        // If fetch fails, show clean message
         els.viewer.innerHTML = `<h1>${section}</h1><p>No content yet.</p>`;
       }
     } else {
-      // No index file → show posts
       els.sectionSelect.value = section;
       renderList();
       loadDefaultForSection(section);
@@ -37,4 +172,38 @@ async function handleHash() {
     }
     file.ext === ".md" ? await renderMarkdown(file.path) : renderIframe(file.path);
   }
-}
\ No newline at end of file
+}
+
+async function renderMarkdown(rel) {
+  const src = await fetch(rel).then(r => r.ok ? r.text() : "");
+  els.viewer.innerHTML = `<article class="markdown">${marked.parse(src || "# Untitled")}</article>`;
+}
+
+function renderIframe(rel) {
+  const iframe = document.createElement("iframe");
+  iframe.src = "/" + rel;
+  iframe.loading = "eager";
+  iframe.setAttribute("sandbox", "allow-same-origin allow-scripts allow-forms");
+  els.viewer.appendChild(iframe);
+
+  iframe.onload = () => {
+    try {
+      const doc = iframe.contentDocument;
+      const style = doc.createElement("style");
+      style.textContent = `
+        html,body{background:#0b0b0b;color:#e6e3d7;font-family:Inter,sans-serif;margin:0;padding:2rem;}
+        *{max-width:720px;margin:auto;}
+        img, video, iframe {max-width:100%;height:auto;}
+      `;
+      doc.head.appendChild(style);
+    } catch (e) {}
+  };
+}
+
+function renderDefault() {
+  const latest = indexData.flat.filter(f => !f.isIndex).sort((a,b) => b.mtime - a.mtime)[0];
+  if (latest) location.hash = `#/${latest.path}`;
+  else els.viewer.innerHTML = "<h1>Welcome</h1><p>Add content to begin.</p>";
+}
+
+init();
\ No newline at end of file