body {
  font-family: Arial, sans-serif;
  background: #f9f9f9;
  padding: 40px;
  display: flex;
  justify-content: center;
}

.container {
  background: white;
  padding: 30px;
  border-radius: 10px;
  max-width: 500px;
  width: 100%;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  text-align: center;
}

input {
  width: 100%;
  padding: 12px;
  margin: 10px 0;
  font-size: 16px;
}

button {
  padding: 12px 20px;
  margin-top: 10px;
  font-size: 16px;
  width: 100%;
}

.result {
  margin-top: 20px;
  font-size: 24px;
  font-weight: bold;
}