Q:

How to make each Div is a section that occupies the entire height of Body?

How to implement the following:
I want a div spans the width and height of the body, and when you scroll down you see another Div occupy the same width and height of the body, as shown in the following page
https://www.lexcorp.io/#/home
How is this possible?

A:

Use viewport units.

Viewport-percentage lengths defined a length relatively to the size of viewport, that is the visible portion of the document. Only Gecko-based browsers are updating the viewport values dynamically, when the size of the viewport is modified (by modifying the size of the window on a desktop computer or by turning the device on a phone or a tablet).

div {
height:100vh; 
max-height:100vh;
}

CanIUse.com - Viewport Units

