{eyou:php}
$field['new_title'] = str_replace($eyou['field']['keywords'], '<span style="color: #ff0000;">' . $eyou['field']['keywords'] . '</span>', $field['title']);
{/eyou:php}
<li>
<a href="{$field.arcurl}" title="{$field.title}">{$field.new_title}</a>
</li>
{/eyou:list}
盡量別用span標簽，可能會覆蓋原來樣式，用b標簽或em更合適些
'<span style="color: #ff0000;">' . $eyou['field']['keywords'] . '</span>',改為'<b style="color: #ff0000;">' . $eyou['field']['keywords'] . '</b>',