Can I color table columns using CSS without coloring individual cells?

Answer 1

I would use the nth-child css pseudo-class for this:

tr td:nth-child(2), tr th:nth-child(2), tr td:nth-child(3), tr td:nth-child(4), tr th:nth-child(4), tr td:nth-child(6), tr td:nth-child(7){
    background-color: #DDD;
}

tr td:nth-child(2),
tr th:nth-child(2),
tr td:nth-child(3),
tr td:nth-child(4),
tr th:nth-child(4),
tr td:nth-child(6),
tr td:nth-child(7) {
  background-color: #DDD;
}

<table border="1">
  <tr>
    <th>Motor</th>
    <th colspan="3">Engine</th>
    <th>Car</th>
    <th colspan="2">Body</th>
  </tr>
  <tr>
    <td>1</td>
    <td>2</td>
    <td>3</td>
    <td>4</td>
    <td>5</td>
    <td>6</td>
    <td>7</td>
  </tr>
  <tr>
    <td>7</td>
    <td>1</td>
    <td>2</td>
    <td>3</td>
    <td>4</td>
    <td>5</td>
    <td>6</td>
  </tr>
</table>

Answer 2

This is an old question with a lot of great answers. Just wanted to add the -n and nth-last-child selectors that haven't yet been mentioned. They're helpful when applying CSS to multiple columns but may not know the number of columns prior to styling, or have multiple tables with varying widths.

/* Select the first two */
table tr td:nth-child(-n + 2) {
  background-color: lightblue;
}

/* Select all but the first two */
table tr td:not(:nth-child(-n + 2)) {
    background-color:lightgreen;
}

/* Select last two only */
table tr td:nth-last-child(-n + 2) {
  background-color:mistyrose;
}

/* Select all but the last two */
table tr td:not(:nth-last-child(-n + 2)) {
    background-color:yellow;
}

jsFiddle: https://jsfiddle.net/3rpf5oht/2/