* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.slider {
    height: 100vh;
    position: relative;
}

.slider img {
    object-fit: cover;
    height: 100%;
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    transition: opacity .5s;
}

.slider img.active {
    opacity: 1;
}