body {
  font-family: sans-serif;
  background: #0d1117;
  color: #c9d1d9;
  text-align: center;
  padding: 50px;
}
.container {
  max-width: 600px;
  margin: auto;
  background: #161b22;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 0 10px rgba(0,0,0,0.3);
}
input {
  width: 100%;
  padding: 10px;
  font-size: 1em;
}
button {
  margin-top: 10px;
  padding: 10px 20px;
  background: #238636;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}