body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #111;
  color: #fff;
  padding: 20px;
}
input, button {
  padding: 10px;
  margin: 10px;
  font-size: 18px;
}
.container {
  max-width: 400px;
  margin: auto;
  background: #222;
  padding: 20px;
  border-radius: 10px;
}