EG Z-Index

The A, B, and C are each contained by different spans. Each of span is contained by the body and is absolutely positioned within the body.

The A span does not have its z-index property set so it shows above the items in the browser window.
The B span has its z-index property set to -1 so it shows underneath everything on the browser window that have a default z-index of 0.
The C span has its z-index property set to 1 so it shows above the A span.

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