Open the login.php file,
Find<td>
<?php echo _NO_ACCOUNT; ?>
<a href="<?php echo sefRelToAbs( 'index.php?option=com_registration&task=register' ); ?>">
<?php echo _CREATE_ACCOUNT; ?></a>
</td>
Change to<td class="register">
<?php echo _NO_ACCOUNT; ?>
<a href="<?php echo sefRelToAbs( 'index.php?option=com_registration&task=register' ); ?>">
<?php echo _CREATE_ACCOUNT; ?></a>
</td>
Now add the following to your stylesheets with your modifications
td.register{
}