<h1>grid-template-rows: 40px 60px;</h1>
<div class="grid-container container1">
  <div class="grid-item">40px</div>
  <div class="grid-item">60px</div>
</div>

<h1>grid-template-rows: 1fr 1.5fr;</h1>
<div class="grid-container container2">
  <div class="grid-item">1fr</div>
  <div class="grid-item">1.5fr</div>
</div>

.grid-container {
  display: grid;
  margin-bottom: 10px;
  padding: 5px;
  background-color: #ccc;
}

.grid-item {
  margin: 5px;
  padding: 10px;
  background-color: yellow;
}

.container1 {
  grid-template-rows: 40px 60px;
}

.container2 {
  grid-template-rows: 1fr 1.5fr;
}