body {
  font-family: Arial, sans-serif;
  background: #f2f2f2;
  margin: 0;
  padding: 20px;
}

.container {
  background: white;
  padding: 20px;
  border-radius: 10px;
  max-width: 400px;
  margin: auto;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

input, button {
  width: 100%;
  padding: 10px;
  margin: 10px 0;
}

#resultado {
  margin-top: 20px;
  font-weight: bold;
}