Table z values determine how individual cells layer within a grid, dashboard, or design system. Understanding these values helps teams control stacking order and visual hierarchy across complex interfaces.
When interfaces scale from simple widgets to dense data views, z management becomes a practical concern rather than a theoretical one. The table below captures common patterns and configuration options used by product and engineering teams.
| Context | Base Z | Overlay Z | Tooltip Z |
|---|---|---|---|
| Dashboard Panel | 10 | 50 | 90 |
| Sidebar | 20 | 60 | 100 |
| Modal | 100 | 200 | 250 |
| Toast | 150 | 250 | 300 |
Design Systems and Z Index Tokens
Design systems define tokenized z index values to standardize layer decisions across products. Teams map tokens such as base, overlay, popover, and modal to numeric values, which are then documented in a shared table.
Implementation in CSS Frameworks
CSS frameworks often expose classes like .z-10, .z-50, and .z-auto to apply numeric offsets directly in markup. This approach reduces context switching between designers and developers and supports rapid experimentation with stacking contexts.
Responsive and Dynamic Adjustments
Responsive layouts may shift table z values at different breakpoints, ensuring touch targets and overlays remain reachable on mobile. Conditional logic in components can also elevate modals above sidebars on small screens, avoiding clipped content and awkward scrolling traps.
Debugging and Maintenance Practices
Debugging stacking issues often starts with inspecting computed z index values in browser devtools. Teams maintain a living style guide that references the table z values table, with notes on overrides for accessibility and edge cases involving iframes or shadow DOM.
Operationalizing Table Z Values
- Document token mappings in a shared design system table.
- Coordinate with engineering to implement tokens as CSS variables.
- Test stacking across browsers and inside iframes.
- Audit periodically to remove unused or conflicting z classes.
FAQ
Reader questions
How do I choose the right base z value for a new component?
Start with the design system token, align with the existing table z values, and reserve lower numbers for backgrounds and higher numbers for foreground interactions.
What happens when two overlays conflict in the DOM?
The element with the higher numeric z index renders on top, unless parent stacking contexts impose local limits that must also be adjusted.
Should tooltip z always be higher than modal z?
No, tooltips typically sit below modals to keep focus on the modal content; the table z values example shows tooltip z at 90 and modal base at 100.
Can negative z index values cause rendering issues?
Yes, negative values can push elements behind the viewport or parent containers, leading to clipping or loss of interactivity if parents do not establish a stacking context.