You doing little salad
fixed cannot be related to a div (the div is moving!)
relative parent & absolute child
But if you set the child to be
absolute and parent to be
relative you get this idea/trick (otherwise the child position absolute to the body):
Setting an absolute position on any element completely removes the element from the document flow. By default the position is relative to the body element. However, you can set any parent element’s position to relative so that the absolute-positioned element will be positioned relative to that parent element.