body {
  font-family: Arial, sans-serif;
  background: #0f172a;
  color: white;
  margin: 0;
}

.container {
  padding: 20px;
  max-width: 600px;
  margin: auto;
}

h1 {
  text-align: center;
}

button {
  width: 100%;
  padding: 15px;
  margin: 10px 0;
  border: none;
  background: #1e293b;
  color: white;
  font-size: 16px;
  border-radius: 8px;
  cursor: pointer;
}

button:hover {
  background: #334155;
}

.hidden {
  display: none;
}

.card {
  background: #1e293b;
  padding: 20px;
  border-radius: 10px;
}