The z-index property is a CSS property that controls the stacking order of positioned elements along the z-axis (the axis perpendicular to both the x and y axes) in a web page.

In simpler terms, it determines the visual depth or layering of elements on the screen. The element with a higher z-index value appears in front of elements with lower values. Here’s the purpose of the z-index property in points:

• Layering Control: It determines the stacking order of positioned elements along the z-axis. Elements with higher z-index values appear in front of elements with lower values.
• Overlapping Elements: Useful for managing the visibility of overlapping UI components, such as dropdowns, modal dialogues, or tooltips.
• Contextual Stacking: Allows control of stacking order within a specific context when using CSS positioning.
• CSS Animations: Influences stacking order during CSS animations or transitions, ensuring elements appear on top when animated.
• Depth in 3D Space: Provides a sense of depth in 3D space on a 2D screen, allowing developers to control the visual hierarchy of elements.
• User Interface Design: Essential for designing visually dynamic and interactive user interfaces with layered or stacked elements.

Syntax:

selector {
  z-index: value;
}

Components

• selector: The HTML element or class/id selector to which you want to apply the z-index property.
• value: An integer representing the stacking order. Elements with a higher z-index value will appear in front of elements with lower values.