<!DOCTYPE html>
<html>

<head>
  <title>An Accessible Table</title>
  <style type="text/css">
    h1 {text-align:center}
    th {border:1px solid black;
        background-color:#cccccc;}
    td {border:1px solid black; width:400px; height:50px}
  </style>
</head>

<body>
<h1> Table within Another Table</h1>
<table id=t1>
  <tr>
    <th></th>
    <th>Outer Column 2</th>
    <th>Outer Column 3</th>
  </tr>
  <tr>
    <th>Outer Row 2</th>
    <td>Outer Row 2 Column 1</td>
    <td>Outer Row 2 Column 2</td>
  </tr>
  <tr>
    <th>Outer Row 3</th>
    <td>Outer Row 3 Column 1</td>
    <td>
      <table id=t2>
        <tr>
          <th></th>
          <th>Inner Col 2</th>
          <th>Inner Col 3</th>
        </tr>
        <tr>
          <th>Inner Row 2</th>
          <td>Inner Row 2 Col 2</td>
          <td>Inner Row 2 Col 3</td>
        </tr>
        <tr>
          <th>Inner Row 3</th>
          <td>Inner Row 3 Col 2</td>
          <td>Inner Row 3 Col 3</td>
        </tr>
    </td>
  </tr>
</table>
</body>
</html>