body {
  font-family: 'Arial', sans-serif;
  background-color: #f4f4f9;
  margin: 0;
  padding: 0;
}

header {
  text-align: center;
  background-color: #333;
  color: white;
  padding: 1em 0;
}

button {
  background-color: #4CAF50;
  color: white;
  padding: 10px 20px;
  border: none;
  cursor: pointer;
  font-size: 16px;
}

button:hover {
  background-color: #45a049;
}

#leaderboard {
  max-width: 600px;
  margin: 2em auto;
  background-color: white;
  padding: 20px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
}

h2 {
  text-align: center;
  font-size: 24px;
}

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

li {
  background-color: #f2f2f2;
  margin: 10px 0;
  padding: 10px;
  font-size: 18px;
  border-radius: 4px;
}