body {
  font-family: Arial, sans-serif;
  background-color: #f4f7fb;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.card {
  background-color: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  width: 300px;
  text-align: center;
}

h1 {
  font-size: 24px;
  color: #333;
}

input {
  width: 100%;
  padding: 10px;
  margin: 10px 0;
  border: 1px solid #ccc;
  border-radius: 4px;
}

button {
  background-color: #4CAF50;
  color: white;
  padding: 10px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

button:hover {
  background-color: #45a049;
}

.hidden {
  display: none;
}

.hint {
  font-size: 12px;
  color: #888;
}

#result {
  margin-top: 10px;
  color: #333;
}