.slider{
    display: flex;
    z-index: -1;
    position: relative;
    width: 50vh;
    height: 75vh;
    align-items: center;
    
}

.slider img{
    width: 100%;
    height: 100%;    
    transition: opacity 800ms;
} 



#slider img{
    
    opacity: 0;   
    position: absolute;
    object-fit: cover;
}

#slider img.selected {   
    opacity: 1;

}