body {
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', sans-serif;
  background-image: url('https://images.unsplash.com/photo-1503676260728-1c00da094a0b');
  background-size: cover;
  background-position: center;
  color: #fff;
}

.overlay {
  background-color: rgba(0, 0, 0, 0.7);
  padding: 30px;
  min-height: 100vh;
}

header {
  text-align: center;
  margin-bottom: 30px;
}

header h1 {
  font-size: 2em;
  color: #ffcc00;
}

header img {
  width: 100%;
  max-width: 800px;
  border-radius: 10px;
  margin-top: 20px;
}

main {
  max-width: 900px;
  margin: auto;
}

section h2 {
  color: #00bfff;
  margin-top: 30px;
}

section p,
section ul,
blockquote {
  font-size: 1.1em;
  line-height: 1.6;
}

ul {
  padding-left: 20px;
}

blockquote {
  background-color: rgba(255, 255, 255, 0.1);
  border-left: 5px solid #00bfff;
  padding: 15px;
  margin-top: 20px;
  font-style: italic;
}

footer {
  margin-top: 40px;
  text-align: center;
  font-size: 0.9em;
  color: #ccc;
  border-top: 1px solid #666;
  padding-top: 20px;
}

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

.quiz li {
  margin: 10px 0;
  background: #333;
  padding: 10px;
  border-radius: 5px;
  cursor: pointer;
}

.quiz li.correct {
  background-color: #2e7d32;
}

button {
  margin-top: 10px;
  padding: 10px 20px;
  background-color: #ffcc00;
  border: none;
  border-radius: 5px;
  color: #000;
  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background-color: #ffc107;
}