body {
  font-family: Arial, sans-serif;
  background: #ffffff;
  margin: 0;
  padding: 0;
  color: #333;
}
header {
  background: #ff6600;
  padding: 30px;
  text-align: center;
  color: white;
}
header h1 {
  margin: 0;
  font-size: 40px;
}
header p {
  font-size: 20px;
}
.button {
  margin-top: 20px;
  display: inline-block;
  padding: 10px 20px;
  background: white;
  color: #ff6600;
  text-decoration: none;
  border-radius: 5px;
  font-weight: bold;
}
.intro, .challenges {
  padding: 40px;
  text-align: center;
}
footer {
  margin-top: 40px;
  background: #333;
  color: white;
  padding: 20px;
  text-align: center;
  font-size: 14px;
}