Z-index is a powerful feature that allows us to manage visual layers in user interfaces. When used correctly, it creates a logical depth hierarchy.
Core principles for z-index management:
- Establish a baseline z-index value (e.g., 100)
- Use fixed increments (e.g., +10)
- Create layer groups (basic UI, overlays, modals)
- Avoid unnecessary z-index usage
- Establish a global z-index management system
Typical z-index hierarchy:
- Main content: 0-99
- Fixed header/footer: 100-199
- Dropdown menus: 200-299
- Popup/tooltips: 300-399
- Modal windows: 400-499
- Notifications: 500-599
- Critical messages: 600+
In complex applications, z-index management requires understanding stacking context rules.
Well-organized z-index makes the user experience more predictable.