如何使用CSS选择所有元素中第一个出现的类

tr > .notpassed{
  color: red;
  /* your selected css style */
}
tr > .notpassed ~ .notpassed{
  color: black;
   /* your common css style */
}

<table>
    <tr>
        <td class="passed">1</td>
        <td class="passed">2</td>
        <td class="passed">3</td>
        <td class="notpassed">4</td>
        <td class="notpassed">5</td>
        <td class="notpassed">6</td>
    </tr>
    <tr>
        <td class="passed">04:47</td>
        <td class="passed">06:22</td>
        <td class="passed">13:15</td>
        <td class="notpassed">20:07</td>
        <td class="notpassed">20:27</td>
        <td class="notpassed">00:27</td>
    </tr>
</table>