body::after {
    content: "";
    background: url(../../../img/background-images/NuevaLamina.png);
    opacity: 0.5;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    position: absolute;
    z-index: -1;   
    background-repeat: no-repeat; 
    background-size: 100% 100%; background-attachment: fixed;
  }