<!doctype html>
<html lang=en>
  <meta charset=utf-8>
  <title>CSS-contain reference: layout/paint containment on subgrid</title>
  <link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">

<style>
.grid {
  display: grid;
  width: 40px;
  height: 40px;
  grid: [a] repeat(2,15px) [b] / [a] repeat(2,15px) [b];
  gap: 10px;
}

.subgrid {
  display: grid;
  grid: none;
  background: lightgrey;
  grid-area:1/1/3/3;
}

.layout { contain: layout; }
.paint { contain: paint; }

.inner {
  background: blue;
  grid-area:a/a/b/b;
}
</style>

<div class="grid"><div class="subgrid layout"><div class="inner"></div></div></div>
<div class="grid"><div class="subgrid paint"><div class="inner"></div></div></div>
<div class="grid"><div class="subgrid layout"><div class="inner"></div></div></div>
<div class="grid"><div class="subgrid paint"><div class="inner"></div></div></div>