diff --git a/index.html b/index.html
index a3c885b..7a015b4 100644
--- a/index.html
+++ b/index.html
@@ -67,10 +67,11 @@
     <section id="panel-modern" role="tabpanel" aria-labelledby="tab-modern" hidden>
       <section class="elements">
         <h2>Ngũ Hành &amp; ngôn ngữ <small class="mode-tag">(tự phân loại theo màu GitHub)</small></h2>
+        <div id="view-toggle"></div>
         <div class="grid" id="element-grid"></div>
         <p class="legend"></p>
         <details id="debug-panel" hidden></details>
-        <p class="disclaimer">* Phân loại tự động theo màu chính thức GitHub Linguist + quy tắc HSL.</p>
+        <p class="disclaimer">* Mặc định hiển thị TIOBE Top 20 (April 2026). Bấm "Xem tất cả ngôn ngữ" để mở rộng.</p>
       </section>
       <details class="original-image">
         <summary>Ảnh gốc</summary>
diff --git a/js/main.js b/js/main.js
index 898ffa1..38ad124 100644
--- a/js/main.js
+++ b/js/main.js
@@ -1,5 +1,6 @@
 import { classify } from './classify-element.js';
-import { renderGrid, renderError, renderDebugPanel, isBorderline } from './render-elements.js';
+import { renderGrid, renderError, renderDebugPanel, isBorderline, mountViewToggle } from './render-elements.js';
+import { TIOBE_TOP } from './tiobe-top.js';
 
 const HEX_RE = /^#[0-9a-fA-F]{6}$/;
 const LEGEND_TEXT =
@@ -27,15 +28,22 @@ async function init() {
         continue;
       }
       const element = classify(color);
-      buckets[element].push({ name, color });
+      const rank = TIOBE_TOP[name] || null;
+      buckets[element].push({ name, color, rank });
       if (isBorderline(color)) borderline.push({ name, color, element });
     }
 
     for (const key of Object.keys(buckets)) {
-      buckets[key].sort((a, b) => a.name.localeCompare(b.name, undefined, { sensitivity: 'base' }));
+      buckets[key].sort((a, b) => {
+        if (a.rank && b.rank) return a.rank - b.rank;
+        if (a.rank) return -1;
+        if (b.rank) return 1;
+        return a.name.localeCompare(b.name, undefined, { sensitivity: 'base' });
+      });
     }
 
     renderGrid(buckets, gridEl);
+    mountViewToggle(document.getElementById('view-toggle'), document.querySelector('#panel-modern .elements'));
     if (legendEl) legendEl.textContent = LEGEND_TEXT;
     renderDebugPanel({ skipped, borderline }, debugEl);
   } catch (err) {
diff --git a/js/render-elements.js b/js/render-elements.js
index 8cf526d..de3d6fe 100644
--- a/js/render-elements.js
+++ b/js/render-elements.js
@@ -7,15 +7,16 @@ function pickTextColor(hex) {
   return (r * 299 + g * 587 + b * 114) / 1000 >= 128 ? 'black' : 'white';
 }
 
-function buildChip(name, color) {
+function buildChip(name, color, { rank = null } = {}) {
   const span = document.createElement('span');
-  span.className = 'chip';
+  span.className = 'chip' + (rank ? ' chip-tiobe' : ' chip-other');
   span.textContent = name;
   if (color) {
     span.style.background = color;
     span.style.color = pickTextColor(color);
-    span.title = color;
+    span.title = rank ? `${color} · TIOBE #${rank}` : color;
   }
+  if (rank) span.dataset.rank = String(rank);
   return span;
 }
 
@@ -24,22 +25,45 @@ export function renderGrid(buckets, mountEl) {
   const fragment = document.createDocumentFragment();
   for (const { key, label } of ELEMENTS) {
     const langs = buckets[key] || [];
+    const tiobeCount = langs.filter((l) => l.rank).length;
     const card = document.createElement('article');
     card.className = `card ${key}`;
     const h3 = document.createElement('h3');
     h3.textContent = label;
     const count = document.createElement('small');
     count.className = 'card-count';
-    count.textContent = `${langs.length} ngôn ngữ`;
+    count.textContent = tiobeCount
+      ? `${tiobeCount} TIOBE · ${langs.length - tiobeCount} khác`
+      : `${langs.length} ngôn ngữ`;
     const chips = document.createElement('div');
     chips.className = 'chips';
-    for (const { name, color } of langs) chips.appendChild(buildChip(name, color));
+    for (const { name, color, rank } of langs) chips.appendChild(buildChip(name, color, { rank }));
     card.append(h3, count, chips);
     fragment.appendChild(card);
   }
   mountEl.replaceChildren(fragment);
 }
 
+export function mountViewToggle(mountEl, scopeEl) {
+  if (!mountEl || !scopeEl) return;
+  const btn = document.createElement('button');
+  btn.type = 'button';
+  btn.className = 'view-toggle-btn';
+  const labels = {
+    tiobe: 'Xem tất cả ngôn ngữ',
+    all: 'Chỉ TIOBE Top 20',
+  };
+  function apply(view) {
+    scopeEl.classList.toggle('show-all', view === 'all');
+    btn.textContent = labels[view];
+    btn.dataset.view = view;
+    btn.setAttribute('aria-pressed', String(view === 'all'));
+  }
+  btn.addEventListener('click', () => apply(btn.dataset.view === 'all' ? 'tiobe' : 'all'));
+  apply('tiobe');
+  mountEl.replaceChildren(btn);
+}
+
 export function renderError(message, mountEl) {
   if (!mountEl) return;
   const p = document.createElement('p');
diff --git a/js/tiobe-top.js b/js/tiobe-top.js
new file mode 100644
index 0000000..aa7887f
--- /dev/null
+++ b/js/tiobe-top.js
@@ -0,0 +1,25 @@
+// TIOBE Index Top 20, April 2026 snapshot.
+// Keys are exact GitHub Linguist names. Scratch is omitted (not tracked by Linguist).
+// Source: https://www.tiobe.com/tiobe-index/
+
+export const TIOBE_TOP = {
+  'Python': 1,
+  'C': 2,
+  'C++': 3,
+  'Java': 4,
+  'C#': 5,
+  'JavaScript': 6,
+  'Visual Basic .NET': 7,
+  'SQL': 8,
+  'R': 9,
+  'Pascal': 10,
+  'Perl': 12,
+  'Fortran': 13,
+  'PHP': 14,
+  'Go': 15,
+  'Rust': 16,
+  'MATLAB': 17,
+  'Assembly': 18,
+  'Swift': 19,
+  'Ada': 20,
+};
diff --git a/style.css b/style.css
index 619f1ab..d99e458 100644
--- a/style.css
+++ b/style.css
@@ -278,6 +278,47 @@ body {
   color: var(--fg);
 }
 
+.chip-tiobe {
+  border-color: rgba(0, 0, 0, 0.35);
+  font-weight: 600;
+}
+
+.elements .chip-other { display: none; }
+.elements.show-all .chip-other { display: inline-block; }
+
+#view-toggle {
+  display: flex;
+  justify-content: center;
+  margin: 0 0 1rem;
+}
+
+.view-toggle-btn {
+  font: inherit;
+  font-size: 0.85rem;
+  padding: 0.35rem 0.9rem;
+  border-radius: 999px;
+  border: 1px solid var(--muted);
+  background: var(--card-bg);
+  color: var(--fg);
+  cursor: pointer;
+  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
+}
+
+.view-toggle-btn:hover {
+  border-color: var(--accent);
+}
+
+.view-toggle-btn[aria-pressed="true"] {
+  background: var(--accent);
+  color: #fff;
+  border-color: var(--accent);
+}
+
+.view-toggle-btn:focus-visible {
+  outline: 2px solid var(--gold);
+  outline-offset: 2px;
+}
+
 .legend {
   text-align: center;
   font-style: italic;