<table class="table-grid">
		<tr>
				<td>
						First cell in main table. 
				</td>
				<td>
						<table class="table-grid">
								<tr>
										<td>
												First cell in, first nested table. 
										</td>
										<td>
												<table class="table-grid">
														<tr>
																<td>
																	Second nested table,	nested table, cell
																</td>
														</tr>
														<tr>
																<td>
																		Second nested table,	nested table, cell
																</td>
														</tr>
												</table>
										</td>
								</tr>
						</table>
				</td>
		</tr>
</table>

.table-grid{

  border-collapse: collapse;
}
.table-grid > tr > td {
  padding: 0;
}

.table-grid>thead>tr>th,
.table-grid>tbody>tr>th,
.table-grid>tfoot>tr>th,
.table-grid>thead>tr>td,
.table-grid>tbody>tr>td,
.table-grid>tfoot>tr>td {
  border: 1px solid red;
}

.table-grid .table-grid td
{
  border-top:0;
  border-right: 1px solid red;
  border-bottom: 0;
  border-left: 0;
}

.table-grid .table-grid td:last-child,
.table-grid .table-grid th:last-child {
  border-right: 0;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.