formular to calculate width/height (relative to parent) of container with translateZ inside of parent container with perspective

Question

What is the formular to calculate the widths/heights of child elements with translateZ inside of parent container with set perspective (keyword: &

Answer 1

I have changed the style slightly, to make things more visible.

The result seems ok for me. May be I am misunderstanding something?

html, body {
  height: 100%;
  overflow: hidden;
  width: 100%;
}

#projection {
  perspective: 1px;
  perspective-origin: 0 0;
  height: 50%;
  overflow: visible;
  width: 50%;
  margin-left: 50px;
  background-color: grey;
}

.pro {
  transform: scale(1) translate(0px, 0px) translateZ(0px);
  height: 50%;
  position: absolute;
  transform-origin: 0 0;
  transform-style: preserve-3d;
  width: 100%;
}

.pro--1 {
  transform: scale(4) translate(0px, 0px) translateZ(-3px);
  width: 110%;
}

.pro--2 {
  transform: scale(3) translate(0px, 120%) translateZ(-2px);
  width: 110%;
}

.pro--3 {
  transform: scale(2) translate(0px, 240%) translateZ(-1px);
  width: 110%;
}

.pro--1 {
  background: rgba(0, 0, 75, 0.5);
  color: blue;
  line-height: 1em;
  text-align: center;
}

.pro--2 {
  background: rgba(0, 75, 0, 0.5);
  color: green;
  line-height: 4em;
}

.pro--3 {
  background: rgba(75, 0, 0, 0.5);
  color: red;
  line-height: 7em;
}

  
pro--1
  
pro--2
  
pro--3