STACK-001 / RUNTIME

Element is trapped in a stacking context

A high z-index remains constrained by an ancestor stacking context.

Rule v1.0.0 Safety Tier C 日本語

Diagnosis

What this finding means

A high z-index remains constrained by an ancestor stacking context.

A finding is not a verdict. Check the displayed evidence and the design intent before changing production code.

Detection

How CSS Doctor detects it

  1. CSS Doctor isolates the pasted HTML and CSS in a sandboxed iframe.
  2. Static rules inspect source structure; runtime rules measure the rendered result.
  3. Evidence is ranked by intent, severity, confidence, affected area, and fix safety.

Before / After

Minimal example

Before review

Review the rendered element and its ancestors.

Possible direction

Choose the narrowest change after comparing before and after.

The example is a starting point, not a universal patch. CSS Doctor previews Tier A and B changes before applying them and never auto-applies Tier C guidance.

Limitations

Limits and manual checks

Choosing which ancestor to change depends on surrounding UI.

  • Production stylesheets not pasted into the tool are not fetched.
  • JavaScript is never executed from user input.
  • Verify the result at all breakpoints and with keyboard input.

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