<div id="container"> <!-- container -->
  <div id="itemA">A</div> <!-- item -->
  <div id="itemB">B</div> <!-- item -->
  <div id="itemC">C</div> <!-- item -->
</div>

#container {
  display: grid;
  grid-template-rows: 200px 50px;
  grid-template-columns: 150px 1fr;
}
#itemA {
	grid-row: 1 / 3;
  grid-column: 1 / 2;
	background: #fecb2f;
	color: #fff;
}
#itemB {
	grid-row: 1 / 2;
  grid-column: 2 / 3;
	background: darkseagreen;
	color: #fff;
}
#itemC {
  grid-row: 2 / 3;
  grid-column: 2 / 3;
  background: lightblue;
  color: #fff;
}