.nube {
    position: absolute;              
    background: white;             
    border-radius: 50px;            
    width: 120px;                    
    height: 40px;                    
    top: 80px;                       
    animation: moverNube 20s linear infinite; 
    opacity: 0.9;                    
  }
  
  .nube::before, .nube::after {
    content: '';                    
    position: absolute;             
    background: white;              
    width: 60px;                    
    height: 60px;
    border-radius: 50%;             
    top: -20px;                     
  }
  
  .nube::before { left: 10px; }     
  .nube::after { right: 10px; }      
  
  .nube1 { left: -150px; animation-delay: 0s; }    
  .nube2 { left: -300px; top: 150px; animation-delay: 10s; } 
  
  @keyframes moverNube {
    from { transform: translateX(0); }      
    to { transform: translateX(120vw); }     
  }