body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
  background: #f5f7fa;
  color: #333;
}

header {
  background: #0b3c5d;
  color: #fff;
  padding: 40px 20px;
  text-align: center;
}

header .btn {
  display: inline-block;
  margin-top: 15px;
  padding: 10px 20px;
  background: #1d7af3;
  color: #fff;
  text-decoration: none;
  border-radius: 4px;
}

section {
  padding: 30px 20px;
  max-width: 900px;
  margin: auto;
}

footer {
  background: #222;
  color: #ccc;
  text-align: center;
  padding: 15px;
}