diff --git a/js/theme.js b/js/theme.js
new file mode 100644
index 0000000..4cfbb77
--- /dev/null
+++ b/js/theme.js
@@ -0,0 +1,22 @@
+function toggleTheme() {
+    const body = document.body;
+    const btn = document.getElementById('toggle-theme');
+    body.classList.toggle('light-mode');
+
+    if (body.classList.contains('light-mode')) {
+        btn.textContent = '🌙';
+        localStorage.setItem('theme', 'light');
+    } else {
+        btn.textContent = '☀️';
+        localStorage.setItem('theme', 'dark');
+    }
+}
+
+(function() {
+    const theme = localStorage.getItem('theme');
+    const btn = document.getElementById('toggle-theme');
+    if (theme === 'light') {
+        document.body.classList.add('light-mode');
+        if (btn) btn.textContent = '🌙';
+    }
+})();
\ No newline at end of file