Why my z-index doesn't work ?plz help me....look the code and give me solution..plz plz plz

Question

https://code.sololearn.com/W2m4tSD8LTHn/?ref=app

Answer 1

Your z-index value is for a span object that is in a div, which in turn is in a header. Your nav overlaps this header because no z-index is specified for the header, which in turn causes all inner elements to overlap, no matter what their z-index is. hence the conclusion: z-index only affects objects that are at the same level of the DOM tree.