* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f9f9f9;
  color: #333;
  line-height: 1.6;
}

nav {
  background-color: #111;
  color: white;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 1000;
}

nav .logo {
  font-size: 1.5rem;
  font-weight: bold;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 1.5rem;
}

nav ul li a {
  color: white;
  text-decoration: none;
  transition: color 0.3s;
}

nav ul li a:hover {
  color: #ffc107;
}

nav .menu-toggle {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 1.4rem;
}

@media (max-width: 700px) {
  nav ul {
    display: none;
    flex-direction: column;
    background-color: #111;
    position: absolute;
    top: 60px;
    left: 0;
    width: 100%;
    padding: 1rem;
  }

  nav .menu-toggle {
    display: block;
  }
}

section {
  padding: 2rem;
  background: white;
  margin: 1rem auto;
  max-width: 900px;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

section h1, section h2 {
  margin-bottom: 1rem;
}

#intro {
  text-align: center;
  padding: 4rem 2rem;
}

#intro h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

#intro button {
  padding: 0.8rem 1.5rem;
  font-size: 1rem;
  background-color: #28a745;
  border: none;
  color: white;
  border-radius: 5px;
  cursor: pointer;
  transition: background 0.3s;
}

#intro button:hover {
  background-color: #218838;
}

.hidden {
  display: none;
}

.active {
  opacity: 1;
  transition: opacity 0.8s ease;
}