Bảng thời gian mọc lặn

<style>
table {
    border-collapse: collapse;
    width: 100%;
}

td.wy, th.wy {
    border: 1px solid #dddddd;
    text-align: center;
    padding: 8px;
}
</style>
<table>
  <tr>
    <th class="wy" rowspan="2">Ngày tháng</th>
    <th class="wy" colspan="2">Mặt Trời</th>
    <th class="wy" colspan="2">Mặt Trăng</th>
  </tr>
  <tr>
    <td class="wy">Mọc</td>
    <td class="wy">Lặn</td>
    <td class="wy">Mọc</td>
    <td class="wy">Lặn</td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
  <tr>
  <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
    <td class="wy"></td>
  </tr>
</table>