.carousel-item img {  
  object-fit: cover;
  object-position: center;
  overflow: hidden;
  height:450px;
}

#carouselHero .carousel-item:before {
  content: '';
  display: block;
  position: absolute;
  background-image: 
    linear-gradient(
      to bottom,
      rgba(0, 0, 0, 0),
      rgba(0, 0, 0, .5)
    );
  width: 100vw;
  top: 0;
  height: 100vh;
}

.carousel-control-next,
.carousel-control-prev /*, .carousel-indicators */ {
    filter: invert(100%);
}