<input type="radio" name="transformStyle" class="hidden" id="ts-flat" checked>
<input type="radio" name="transformStyle" class="hidden" id="ts-preserve">

<div class="container">
  <div class="square A"></div>
  <div class="square B"></div>
  <div class="square C"></div>
</div>

<div class="options">

  <h3>transform-style:</h3>
  <label for="ts-flat" class="transformStyle flat">flat</label>
  <label for="ts-preserve" class="transformStyle preserve">preserve-3d</label>
</div>

@import url("https://fonts.googleapis.com/css2?family=Anton&display=swap");

*, *::before, *::after {
  padding: 0;
  margin: 0 auto;
  box-sizing: border-box;
}

body {
  font-family: 'Anton', sans-serif;
  background-color: #eee;
  color: #333;
  min-height: 100vh;
  display: -webkit-box;
  display: flex;
  -webkit-box-pack: center;
          justify-content: center;
  align-content: center;
  -webkit-box-align: center;
          align-items: center;
  flex-wrap: wrap;
}

.hidden {
  position: fixed;
  top: -10000px;
  left: -10000px;
  visibility: hidden;
}

.container {
  position: relative;
  width: 280px;
  height: 200px;
  border: 1px solid #fff;
  border-radius: 4px;
  display: -webkit-box;
  display: flex;
  -webkit-box-pack: center;
          justify-content: center;
  -webkit-box-align: center;
          align-items: center;
  margin: 1em;
  -webkit-perspective: 1000px;
          perspective: 1000px;
}

.square {
  width: 100px;
  height: 100px;
  -webkit-transform: rotateY(-30deg);
          transform: rotateY(-30deg);
  position: absolute;
}

.square.A {
  background-color: green;
  -webkit-transform: rotateY(-30deg) translateZ(100px);
          transform: rotateY(-30deg) translateZ(100px);
}

.square.B {
  background-color: #D50000;
}

.square.C {
  background-color: #304FFE;
  -webkit-transform: rotateY(-30deg) translateZ(-100px);
          transform: rotateY(-30deg) translateZ(-100px);
}

.options {
  margin: 1em;
}

label {
  display: inline-block;
  padding: 0.5em 1em;
  border: 1px solid #777;
  border-radius: 4px;
}

#ts-flat:checked ~ .container {
  -webkit-transform-style: flat;
          transform-style: flat;
}

#ts-flat:checked ~ .options > label.flat {
  background-color: greenyellow;
}

#ts-preserve:checked ~ .container {
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
}

#ts-preserve:checked ~ .options > label.preserve {
  background-color: greenyellow;
}