#header {
  transition: background-color 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
}
#header.scrolled {
  background-color: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.07), 0 1px 2px -1px rgb(0 0 0 / 0.07);
}