.carousel-item {
  height: 100vh; 
  min-height: 300px;
  background: no-repeat top center scroll;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

.layer {
    background-color: rgba(6, 12, 34, 0.5);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}