Feature: Dark Mode Toggle Added (#179)

README.md

@@ -5,3 +5,6 @@ This book will teach you the basics of programming and Javascript. Whether you a
 ![](./assets/intro.png)
 
 JavaScript (_JS for short_) is the programming language that enables web pages to respond to user interaction beyond the basic level. It was created in 1995, and is today one of the most famous and used programming languages.
+<link rel="stylesheet" href="assets/darkmode.css">
+<script src="assets/darkmode.js"></script>
+

assets/darkmode.css

@@ -0,0 +1,12 @@
+body.dark {
+  background-color: #121212;
+  color: #f0f0f0;
+}
+
+.dark h1, .dark h2, .dark h3 {
+  color: #ffffff;
+}
+
+.dark a {
+  color: #90caf9;
+}

assets/darkmode.js

@@ -0,0 +1,25 @@
+document.addEventListener('DOMContentLoaded', function () {
+  const toggle = document.createElement('button');
+  toggle.innerText = "🌙 Toggle Dark Mode";
+  toggle.style.position = 'fixed';
+  toggle.style.top = '10px';
+  toggle.style.right = '10px';
+  toggle.style.zIndex = '9999';
+  toggle.style.padding = '10px';
+  toggle.style.borderRadius = '5px';
+  toggle.style.border = 'none';
+  toggle.style.backgroundColor = '#333';
+  toggle.style.color = '#fff';
+  toggle.style.cursor = 'pointer';
+
+  toggle.onclick = () => {
+    document.body.classList.toggle('dark');
+    localStorage.setItem('theme', document.body.classList.contains('dark') ? 'dark' : 'light');
+  };
+
+  document.body.appendChild(toggle);
+
+  if (localStorage.getItem('theme') === 'dark') {
+    document.body.classList.add('dark');
+  }
+});