Arbitrary z-indexArbitrary z-index

Why it matters

z-[9999]-style values escalate into stacking wars between overlays.

Fix

Define a small z-index scale in the theme and use its steps.

Credit

• 

  From Josh W. Comeau

  Argues z-index is an escape hatch and that isolation and stacking contexts beat escalating values.

References

• What The Heck, z-index?? — Josh W. ComeauJosh W. Comeau
• Stacking contextMDN Web Docs

See it