My background of a shape come after the image depsite having priority with the z-index?

HTML-CSS
#1 
.body {
  z-index: 1;
  width: 25px;
  height: 50px;
  background: silver;
  position: relative;
  left: 500px;
  top: 50px;
  zoom: 150% ------


#background {
  z-index: 0;
  position: absolute;
  top: -450px;
  left: -490px;
  animation: img 10s linear;
  animation-fill-mode: forwards;
#2

Hi @torekcandoit. What is your question?

#3