Result Size: 625 x 664
x
 
<!DOCTYPE html>
<html>
<head>
<style>
.grid-container {
  display: grid;
  grid-template: auto / auto auto auto auto;
  grid-gap: 10px;
  background-color: #2196F3;
  padding: 10px;
  animation: mymove 5s infinite;
}
.grid-container > div {
  background-color: rgba(255, 255, 255, 0.8);
  text-align: center;
  padding: 20px 0;
  font-size: 30px;
}
@keyframes mymove {
  50% {grid-template: 100px / auto auto;}
}
</style>
</head>
<body>
<h1>Animation of the grid-template Property</h1>
<p>The animation will change the grid layout.</p>
<div class="grid-container">
  <div class="item1">1</div>
  <div class="item2">2</div>
  <div class="item3">3</div>  
  <div class="item4">4</div>
  <div class="item5">5</div>
  <div class="item6">6</div>
  <div class="item7">7</div>
  <div class="item8">8</div>
</div>
</body>
</html>