/* Ocupa toda la pantalla */
.preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: #ffffff;
    z-index: 9999;
}

/* Animación de onda */
.preloader .spinner-grow {
    margin: 0 5px;
    opacity: 0;
    transform: scale(0.5);
    animation: wave 1.5s infinite;
}

.preloader .spinner-grow:nth-child(1) { animation-delay: 0s; }
.preloader .spinner-grow:nth-child(2) { animation-delay: 0.2s; }
.preloader .spinner-grow:nth-child(3) { animation-delay: 0.4s; }
.preloader .spinner-grow:nth-child(4) { animation-delay: 0.6s; }
.preloader .spinner-grow:nth-child(5) { animation-delay: 0.8s; }

@keyframes wave {
    0%, 80%, 100% { opacity: 0; transform: scale(0.5); }
    40% { opacity: 1; transform: scale(1.2); }
}