<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
table, th, td {
border: 1px solid black;
border-collapse: collapse;
}
table.center {
margin-left: auto;
margin-right: auto;
}
</style>
</head>
<body>
<h2>Center a Table</h2>
<p>To center a table, set left and right margin to auto:</p>
<table class="center">
<tr>
<th>Firstname</th>
<th>Lastname</th>
<th>Age</th>
</tr>
<tr>
<td>Jill</td>
<td>Smith</td>
<td>50</td>
</tr>
<tr>
<td>Eve</td>
<td>Jackson</td>
<td>94</td>
</tr>
<tr>
<td>John</td>
<td>Doe</td>
<td>80</td>
</tr>
</table>
</body>
</html>