body {
  background-color: #2f4f3e; /* verde pantano */
  margin: 0;
}

.fondo {
  background-image: url("img/fondo.png/6d1863fb9f5f05a01b151bfa3f98fc3b.jpg");
  background-size: cover;
  background-position: center;
  min-height: 100vh;
  background-attachment: scroll; /* se mueve al bajar */
}

.contenido {
  background-color: rgba(255, 255, 255, 0.85);
  padding: 20px;
  max-width: 700px;
  margin: auto;
}