body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  background: #f9f9f9;
  color: #333;
}

header, section, footer {
  max-width: 600px;
  margin: auto;
  padding: 20px;
}

header h1 {
  text-align: center;
  color: #2c3e50;
}

button {
  padding: 10px 20px;
  margin: 10px 5px 0 0;
  border: none;
  background: #3498db;
  color: white;
  cursor: pointer;
  border-radius: 5px;
  font-size: 16px;
}

button:hover {
  background: #2980b9;
}

.hidden {
  display: none;
}

#quiz-container {
  background: white;
  border-radius: 8px;
  padding: 20px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

#progress {
  margin-bottom: 15px;
  font-weight: bold;
}

#answer-buttons button {
  display: block;
  width: 100%;
  margin: 5px 0;
}

footer {
  text-align: center;
  font-size: 14px;
  color: #555;
}

#ad-banner {
  margin-top: 15px;
  background: #eee;
  padding: 10px;
  text-align: center;
  border-radius: 5px;
}