Ошибка в проверке задания.
<!DOCTYPE html>
<html>
<head>
<title>Grid layout</title>
<style>
body {
margin: 0;
}
.grid-container {
display: grid;
grid-template-columns: [start col-1-end] 20vw [col-2-start col-2-end] auto [col-3-start end] 20vw;
grid-template-rows: [line1] auto [line2] 20vh [line3] 20vh [line4] auto [line5];
height: 100vh;
width: 100vw;
}
.grid-item {
background-color: rgb(255, 198, 0);
padding: 2vw;
font-size: 10vw;
font-style: italic;
font-family: Tahoma;
}
</style>
</head>
<body>
<div class="grid-container">
<div class="grid-item">
Center Me
</div>
</div>
</body>
</html>