.banner {
  position: relative;
  width: 100%;
  height: 100%; 
  background-image: url('https://static.tildacdn.com/tild3863-3639-4365-a261-353839303965/DSC08809.jpg');
  background-size: cover;
  background-position: center;
  background-color: black; 
}
.banner::before, .banner::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  width: 15%; 
  background: linear-gradient(to left, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 1) 100%); 
  filter: blur(0px);
  z-index: 1;
}

.banner::before {
  left: 0; 
}

.banner::after {
  right: 0; 
  background: linear-gradient(to right, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 1) 100%); 
  
}