body {
  font-family: Arial, sans-serif;
  background: #121212;
  color: white;
  margin: 0;
  padding: 20px;
}

.container {
  max-width: 700px;
  margin: auto;
}

h1 {
  text-align: center;
}

.card {
  background: #1f1f1f;
  padding: 16px;
  border-radius: 12px;
  margin-bottom: 16px;
}

input {
  width: 100%;
  padding: 10px;
  margin-top: 6px;
  margin-bottom: 12px;
  border-radius: 8px;
  border: none;
  font-size: 16px;
}

button {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 12px;
  font-size: 18px;
  cursor: pointer;
}

.result {
  font-size: 18px;
}