css-stacking-contexts

Your z-index is likely not working because a parent element created a new stacking context via properties like transform, opacity, or isolation. Analyzing element positioning and stacking context inheritance resolves these unpredictable UI layering conflicts.

CSS properties that create a new stacking context include z-index with a positioned element, opacity values less than 1, transforms, and isolation. Auditing these properties helps diagnose why overlays, sticky headers, and tooltips are trapped behind other elements.

Fix a trapped modal or tooltip by adjusting z-index relationships, applying isolation to isolate its parent, or restructuring the DOM hierarchy. Generating a prioritized remediation plan ensures minimal, robust strategies for repairing complex layered components.

The best way to audit complex stacking contexts is systematically tracing which elements create or inherit contexts through their CSS properties. This process produces a clear layering map and validation checks to resolve UI conflicts across web projects.

Using opacity or transform directly affects z-index layering because both properties create a new stacking context. This confines child elements within the parent's layering limits, requiring a structured audit to restructure DOM and fix overlay visibility.

Use the CSS isolation property when you need to create a new stacking context without relying on transforms or opacity. It isolates a parent element's layering, preventing child components like tooltips and modals from conflicting with external z-index values.