<!DOCTYPE html>
<html>
<head>
<style>
.grid-container {
display: grid;
grid-gap: 10px;
grid-template-columns: auto auto auto;
background-color: blue;
padding: 10px;
}
.grid-container > div {
background-color: lightblue;
border: 1px solid;
padding: 15px;
}
/* grid-item1 start with row line 1 column line 3
and end with row line 2 column line 4 */
.grid-item1 { grid-area: 1 / 3 / 2 / 4; }
.grid-item2 { grid-area: 1 / 2 / 1 / 3; }
.grid-item3 { grid-area: 1 / 1 / 2 / 2; }
.grid-item4 { grid-area: 2 / 1 / 3 / 2; }
.grid-item5 { grid-area: 2 / 2 / 3 / 3; }
.grid-item5 { grid-area: 2 / 3 / 3 / 4; }
</style>
</head>
<body>
<div class="grid-container">
<div class="grid-item1">a</div>
<div class="grid-item2">b</div>
<div class="grid-item3">c</div>
<div class="grid-item4">d</div>
<div class="grid-item5">e</div>
<div class="grid-item6">f</div>
</div>
</body>
</html>