<table> <thead> <tr> <th>この行に</th> <th>ヒット</th> </tr> </thead> <tbody> <tr> <td>この行に</td> <td>ヒット</td> </tr> <tr> <td>hoge</td> <td>fuga</td> </tr> </tbody> </table>
table tr:first-of-type{ background-color: red; }