This content originally appeared on DEV Community and was authored by Pawar Shivam
=> Why z-index Is Not Working?
You write this:
.modal {
position: absolute;
z-index: 9999;
}
But still…
👉 It appears behind other elements.
=> The Real Problem
z-index only works within the same stacking context.
If elements are in different contexts → values don’t compare.
=> What Creates a Stacking Context
Many developers don’t know this.
These properties create new stacking contexts:
position: relative;
z-index: value;
opacity: < 1;
transform: translateZ(0);
filter: blur(0);
=> Common Bug Example
.parent {
position: relative;
z-index: 1;
}
.child {
position: absolute;
z-index: 9999;
}
If another element is outside this parent:
👉 It can still appear above .child
=> Why This Happens
Because .child is trapped inside .parent stacking context.
It cannot escape.
=> The Fix
Move element outside or remove stacking context:
.parent {
position: static;
}
Or:
👉 Move modal directly under <body>
=> Real UI Tip
For modals, dropdowns, overlays:
👉 Avoid deep nesting
👉 Render at top level
=> What Developers Often Miss
It’s not about increasing z-index.
It’s about understanding stacking context.
=> What Do You Think?
Have you ever tried z-index: 9999 and it still didn’t work?
This content originally appeared on DEV Community and was authored by Pawar Shivam
Pawar Shivam | Sciencx (2026-03-23T17:06:22+00:00) Why z-index Doesn’t Work (And How to Fix It). Retrieved from https://www.scien.cx/2026/03/23/why-z-index-doesnt-work-and-how-to-fix-it/
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