HTML table: column width percentage

Question

I have a table with 7 columns. I want the columns to be of the following widths:

• 3 columns x width=20%
• 4 columns x width=10%

Answer 1

To fixe width, you can use table-layout:fixed; .

You may also want to use the colgroup and col tags to assign at once width and bg to your columns.

table {
  width: 100%;
  table-layout: fixed;
}
.ten {
  width: 10%;
  background: tomato;
}
.twenty {
  width: 20%;
  background: turquoise
}
/* see me */
td {
  border: solid;
}
/* play with bg cells and cols ? */

tr:nth-child(even) :nth-child(odd) {
  background:rgba(100,255,50,0.3);
  }
tr:nth-child(odd) :nth-child(even) {
  background:rgba(255,255,255,0.3);
  }

<table>
  <colgroup>
    <col class="ten" />
    <col class="ten" />
    <col class="ten" />
    <col class="twenty" />
    <col class="twenty" />
    <col class="twenty" />
    <col class="ten" />
  </colgroup>
  <tr>
    <th>H1</th>
    <th>H2</th>
    <th>H3</th>
    <th>H4</th>
    <th>H5</th>
    <th>H6</th>
    <th>H7</th>
  </tr>

  <tr>
    <td>A1</td>
    <td>A2</td>
    <td>A3</td>
    <td>A4</td>
    <td>A5</td>
    <td>A6</td>
    <td>A7</td>
  </tr>

  <tr>
    <td>B1</td>
    <td>B2</td>
    <td>B3</td>
    <td>B4</td>
    <td>B5</td>
    <td>B6</td>
    <td>B7</td>
  </tr>
 <tr>
    <td>A1</td>
    <td>A2</td>
    <td>A3</td>
    <td>A4</td>
    <td>A5</td>
    <td>A6</td>
    <td>A7</td>
  </tr>

  <tr>
    <td>B1</td>
    <td>B2</td>
    <td>B3</td>
    <td>B4</td>
    <td>B5</td>
    <td>B6</td>
    <td>B7</td>
  </tr>

</table>

Answer 2

Your CSS works as expected, in a way that the widths of the table heads and cells are correct. However:

th by default have text-align: center applied, while the td element has not.

So you should add either to the td or th the same text alignment. E.g.:

th {
    text-align: left;
}