auto
Example:
<!DOCTYPE html>
<html>
<head>
<style>
.grid-container {
display: grid;
grid-template-columns: auto auto auto auto;
grid-gap: 0px;
background-color: #2196F3;
padding: 10px;
}
.grid-container > div {
background-color: rgba(255, 255, 255, 0.8);
text-align: center;
padding: 20px 0;
font-size: 30px;
}
</style>
</head>
<body>
<h1>The grid-template-columns Property</h1>
<p>Use the <em>grid-template-columns</em> property to define the number of columns in the grid layout.</p>
<p>This grid layout has four columns:</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>