In the traditional method, we consider the layout in the two-dimensional space of the plane, that is, the four directions of up, down, left and right. If each module is abstracted into a plane, from the three-dimensional point of view, there is a context.
A page can be regarded as the overlap of n layers, and a two-dimensional page is formed through the mutual perspective between layers. This abstraction is only from the perspective of designing page layout, and has no effect on the two-dimensional vision that is finally presented to users.
The most commonly used two-dimensional layout is to use floating and relative positioning to make various modules squeeze into a plane. In order to take care of compatibility and deal with all kinds of bugs, the structure and performance are often very complicated and the efficiency is greatly reduced.
Absolute positioning must be used for 3D layout. Absolute positioning is easy to cause misunderstanding of fixed layout, which is actually wrong. Absolute positioning can replace floating to a certain extent, which is more compatible. Typical example: absolute positioning adaptive layout, height 100%.