body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #111827;
  color: white;
}

header {
  text-align: center;
  padding: 30px;
  background: #1f2937;
}

header h1 {
  margin: 0;
  font-size: 3rem;
}

nav {
  display: flex;
  justify-content: center;
  gap: 10px;
  padding: 15px;
}

button {
  padding: 10px 18px;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: bold;
}

main {
  padding: 20px;
}

footer {
  text-align: center;
  padding: 20px;
  background: #1f2937;
  margin-top: 40px;
}