AI solution for Interview Question on BFE.dev
9. explain how different CSS `position` property works

The position property in CSS defines how an element will be positioned in the document layout. There are four different values for this property - static, relative, absolute and fixed.

1. static - This is the default position value in CSS, and it means that the element will appear in the normal flow of the page. The top, right, bottom and left properties do not have any effect on statically positioned elements.

2. relative - This position value allows an element to be positioned relatively to its normal position in the document flow. The top, right, bottom and left properties can be used to adjust the position of the element relative to its normal position.

3. absolute - This position value allows an element to be positioned relative to its closest positioned ancestor element, or if there are no positioned ancestor elements, it will be positioned relative to the document body itself. The top, right, bottom and left properties can be used to adjust the position of the element from its relatively positioned ancestor.

4. fixed - This position value allows an element to be positioned relative to the viewport, which means that it will stay in the same position even if the user scrolls the page. The top, right, bottom and left properties can be used to adjust the position of the element from the viewport.

Additionally, there is also a newer position: sticky value. This position value allows an element to be positioned as relative until it reaches a certain scroll threshold, where it will then switch to being fixed. This is often used for sticky headers or menus that follow the user as they scroll down a page.

Finally, it is important to note the concept of stacking context when dealing with CSS position property. In short, every positioned element is part of a stacking context, which defines the relative order in which it will be displayed along with other elements on the page. The stacking order can be changed with the z-index property, but it only affects elements that are part of the same stacking context. Elements with a higher z-index value will be placed in front of elements with a lower z-index value within the same stacking context.