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How does z-index affect stacking order when using position fixed?

Asked on Oct 09, 2025

Answer

The `z-index` property in CSS determines the stacking order of elements that have a position value other than static, such as fixed. It allows you to control which elements appear in front of or behind others.

Example Concept: The `z-index` property affects stacking order by assigning an integer value to positioned elements (e.g., fixed, absolute, relative). Elements with a higher `z-index` value will appear on top of those with a lower value. When using `position: fixed`, the element is removed from the normal document flow and positioned relative to the viewport, allowing it to stay in place as you scroll. The `z-index` then determines its layering in relation to other positioned elements.

Additional Comment:
  • `z-index` only works on elements with a position value other than static.
  • Elements with the same `z-index` value follow the order they appear in the HTML.
  • Negative `z-index` values can place elements behind others, including the background.
  • Consider browser compatibility, as some older browsers may handle `z-index` differently.
✅ Answered with CSS best practices.

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