CSS3 Box-Shadow Showing Behind Sibling Div Element [duplicate]

This question already has answers here: Why does z-index not work? (10 answers) Closed 7 years ago.

I'm using:

开发者_开发知识库box-shadow: 0px -1px 0px #333333;

on my footer but it's hiding behind or disappearing where the div before it is... hard to explain but here's what it looks like: http://cl.ly/7HLy

Is there a way do have the box-shadow be on top of the other div before the footer? I've tried adding a z-index but it doesn't work.

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I'll repeat my comment here since it solved the problem.

When using z-index you should use position: relative;