feat: add powered-by footer for Tertiary Infotech Academy

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: alfredang

index.html

@@ -109,6 +109,10 @@ <h3>Edit Question</h3>
   2. For local dev: rename firebase-config.local.js to firebase-config.js
      or use the local dev server script below
 -->
+<footer class="site-footer">
+  Powered by Tertiary Infotech Academy Pte Ltd
+</footer>
+
 <script src="firebase-config.js"></script>
 <script src="app.js"></script>
 </body>

styles.css

@@ -572,3 +572,12 @@ input, textarea {
 
 @keyframes toastIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
 @keyframes toastOut { from { opacity: 1; } to { opacity: 0; } }
+
+/* ===== FOOTER ===== */
+.site-footer {
+  text-align: center;
+  padding: 16px;
+  font-size: 0.75rem;
+  color: var(--text-muted);
+  letter-spacing: 0.02em;
+}