CSS

blurred background

.bg-blur {
  overflow: hidden;
}
.bg-blur::before {
  content: '';
  background-image: var(--bg-image);
  background-size: cover;
  height: 100%;
  width: 100%;
  position: absolute;
  z-index: -1;
}
.bg-blur::before {
  filter: blur(30px);
}