body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f4f4f4;
  color: #333;
}

header {
  background: #007bff;
  color: #fff;
  padding: 1rem 0;
  text-align: center;
}

header nav a {
  margin: 0 15px;
  color: white;
  text-decoration: none;
  font-weight: bold;
}

header nav a.active {
  text-decoration: underline;
}

main {
  max-width: 900px;
  margin: 20px auto;
  background: white;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  background: #007bff;
  color: white;
  text-decoration: none;
  border-radius: 5px;
}

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