body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #0d0d0d;
  color: #fff;
}

header {
  background-color: #1a1a1a;
  padding: 20px;
  text-align: center;
}

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

nav ul li {
  display: inline-block;
  margin: 0 15px;
}

nav ul li a {
  text-decoration: none;
  color: #00bfff;
  font-weight: bold;
}

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

section {
  margin-bottom: 40px;
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  background-color: #00bfff;
  color: #fff;
  text-decoration: none;
  border-radius: 5px;
}

footer {
  text-align: center;
  padding: 20px;
  background-color: #1a1a1a;
  margin-top: 40px;
}