Efecto slider eliasymuñoz, con el background

.fv-carousel .slide {
. position: relative;
}

.fv-carousel .slide:after {
   background-color: var(--image-transparency-color);
   content: '';
   position: absolute;
   top: 0;
   left: 0;
   height: 100%;
   width: 100%;
   z-index: -1;
}