/* Light mode */
body {
  margin: 100px;
  font-family: "Segoe UI", sans-serif;
  background: #f4f4f9;
  color: #333;
  transition: background 1s, color 1s;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem;
  text-align: center;
}

header h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

header p {
  font-size: 1.2rem;
  color: #666;
}

.btn {
  display: inline-block;
  margin-top: 1.2rem;
  padding: 0.6rem 1.2rem;
  background: #0077b6;
  color: #fff;
  text-decoration: none;
  border-radius: 8px;
  transition: background 0.3s;
  min-width: 60px;
}

.btn:hover {
  background: #005c8e;
}

footer {
  margin-top: 3rem;
  font-size: 0.9rem;
  color: #888;
}

.toggle-btn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: 2px solid #ccc;
  padding: 0.5rem 0.5rem;
  border-radius: 15px;
  cursor: pointer;
  font-size: 1rem;
}

.toggle-btn:hover {
  background: #e1eff2;
}

/* Dark mode */
body.dark {
  background: #121212;
  color: #e0e0e0;
}

body.dark header p,
body.dark footer {
  color: #aaa;
}

body.dark .btn {
  background: #0077b6;
}

body.dark .btn:hover {
  background: #005c8e;
}

body.dark .toggle-btn {
  border-color: #555;
  color: #e0e0e0;
}

body.dark .toggle-btn:hover {
  background: #3b4142;
}