body {
  font-family: 'Arial', sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f9f9f9;
  color: #333;
  scroll-behavior: smooth;
}

header {
  background-color: #007bff;
  color: white;
  padding: 40px;
  text-align: center;
}

nav {
  text-align: center;
  background: #eee;
  padding: 10px;
}

nav a {
  text-decoration: none;
  color: #007bff;
  margin: 0 10px;
}

section {
  padding: 30px;
  max-width: 800px;
  margin: auto;
}

h2 {
  color: #007bff;
}

ul {
  list-style-type: none;
  padding-left: 0;
}

ul li {
  padding: 8px 0;
}

footer {
  text-align: center;
  background-color: #333;
  color: white;
  padding: 15px;
  margin-top: 40px;
}

/* ডার্ক মোড */
body.dark-mode {
  background-color: #1c1c1c;
  color: #f1f1f1;
}

body.dark-mode header {
  background-color: #444;
}

body.dark-mode nav {
  background-color: #333;
}

#darkModeToggle {
  position: fixed;
  top: 10px;
  right: 10px;
  padding: 8px 12px;
  background: #444;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}