.slider .slide {
    background-position: center;
    background-size: contain;
    background-repeat: no-repeat;

    animation: slide 12s infinite;
}

@keyframes slide {
    0%,
    42%,
    100% {
        opacity: 1;
        animation-timing-function: ease;
        z-index: 0;
    }

    50% {
        opacity: 0;
        animation-timing-function: step-end;
        z-index: 0;
    }

    92% {
        opacity: 1;
        animation-timing-function: step-end;
        z-index: -1;
    }
}

.slider a:nth-child(1) .slide {
    background-image: url("https://techupdate.sci.edu.vn/wp-content/uploads/2025/07/background-main.png");
    animation-delay: 0s;
}

.slider a:nth-child(2 ) .slide {
    background-image: url("https://techupdate.sci.edu.vn/wp-content/uploads/2025/10/TechUpdate-2025-Banner-2048px.png");
    animation-delay: -6s;
}

@media screen and (max-width: 768px) {
    .slider .slide {
        background-position: center;
        background-size: contain;
    }
}