The first-child Structural Pseudo-Class
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en'> <head> <title>:first-child</title> <style rel='stylesheet' type='text/css'> table tbody tr:first-child td { background: mediumslateblue; } </style> </head> <body> <h1>A</h1> <table> <thead> <tr> <th>A</th> <th>Y</th> </tr> </thead> <tbody> <tr> <td>L</td> <td>M</td> </tr> </tbody> </table> </body> </html>