<!DOCTYPE html>
<html>
<head>
<style>
.grid-item1 {
grid-area: gArea;
}
.grid-container {
display: grid;
grid-gap: 10px;
/* grid-item1 will take the place of 3 columns */
grid-template-areas: 'gArea gArea gArea';
background-color: blue;
padding: 10px;
}
.grid-container > div {
background-color: lightblue;
border: 1px solid;
padding: 15px;
}
</style>
</head>
<body>
<div class="grid-container">
<div class="grid-item1">A</div>
<div class="grid-item">B</div>
<div class="grid-item">C</div>
<div class="grid-item">D</div>
<div class="grid-item">E</div>
<div class="grid-item">F</div>
<div class="grid-item">G</div>
<div class="grid-item">H</div>
<div class="grid-item">I</div>
<div class="grid-item">J</div>
<div class="grid-item">K</div>
<div class="grid-item">L</div>
<div class="grid-item">M</div>
<div class="grid-item">N</div>
</div>
</body>
</html>