body {
  font-family: Arial, sans-serif;
  background-color: #f3f4f6;
  text-align: center;
  padding: 40px;
}

.container {
  background: white;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  max-width: 500px;
  margin: auto;
}

button {
  padding: 10px 20px;
  font-size: 16px;
  margin: 5px;
  border: none;
  background-color: #007bff;
  color: white;
  border-radius: 6px;
  cursor: pointer;
}

button:hover {
  background-color: #0056b3;
}

#resultado, #historial {
  margin-top: 20px;
  font-size: 18px;
}
#historial {
  max-height: 200px;
  overflow-y: auto;
  background-color: #f8f9fa;
  padding: 10px;
  border-radius: 6px;
  border: 1px solid #dee2e6;
}