body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
}


#bg {
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
}

#bg img {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto;
  max-width: 75%;
  filter: blur(30px) brightness(60%);
  max-height: 75%;
  min-width: 50%;
  min-height: 50%;
}