Slanted diagonal line in html or css?

Question

I want to make a Table like this

is it possible to add a slanted diagonal border in table?

Answer 1

Based on CSS3 linear-gradients solution except that the angle is not hard coded:

table:nth-of-type(1) td {
  background-image: linear-gradient(
    to top right,
    white 48%,
    black,
    white 52%
  );
}
table:nth-of-type(2) td {
  background-image: linear-gradient(
    to top right,
    papayawhip calc(50% - 1px),
    black,
    papayawhip calc(50% + 1px)
  );
}
/* for testing */
table {
  border-collapse: collapse;
  margin-top: 1em;
  margin-bottom: 1em;
}
td:nth-child(odd) {
  width: 10em;
}
td:nth-child(even) {
  width: 20em;
}

<table border="1">
  <tbody>
    <tr>
      <td>Narrow</td>
      <td>Wide</td>
    </tr>
    <tr>
      <td>Narrow</td>
      <td>Wide</td>
    </tr>
  </tbody>
</table>
<table border="1">
  <tbody>
    <tr>
      <td>Narrow</td>
      <td>Wide</td>
    </tr>
    <tr>
      <td>Narrow</td>
      <td>Wide</td>
    </tr>
  </tbody>
</table>