body {
  display: flex;
  justify-content: center;
  min-height: 100vh;
  margin: 0;
}

.contenedor {
  background: white;
  border-radius: 20px;
  max-width: 550px;
  width: 100%;
  margin-top: 60px;
}

h1 {
  text-align: center;
  margin-bottom: 20px;
  margin-top: 0;
  font-size: 28px;
  text-decoration: underline;
}

.generador {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

label {
  font-size: 16px;
  font-weight: bold;
}

input[type="number"] {
  padding: 15px;
  font-size: 18px;
  border: 2px solid #ddd;
  border-radius: 8px;
  outline: none;
  transition: border-color 0.3s;
  text-align: center;
}

input[type="number"]:focus {
  border-color: #667eea;
}

.btn-generar {
  padding: 18px;
  font-size: 18px;
  font-weight: bold;
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s;
  background-color: #5568d3;
}

.resultado {
  padding: 25px;
  background-color: #c3cfe2;
  border-radius: 10px;
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  word-break: break-all;
  border: 2px solid #e0e0e0;
}

.texto-inicial {
  color: #999;
  font-style: italic;
  margin: 0;
}

.contrasena {
  font-size: 24px;
  font-weight: bold;
  font-family: "Courier New", monospace;
  color: #333;
  letter-spacing: 2px;
  margin: 0;
}

.error {
  color: #dc3545;
  font-size: 18px;
  font-weight: bold;
  margin: 0;
}

.volver {
  display: block;
  text-align: center;
  margin-top: 30px;
  padding: 12px 25px;
  background-color: #667eea;
  text-decoration: none;
  color: white;
  border-radius: 10px;
  font-weight: bold;
  transition: all 0.3s;
}