$re = '/\(color:\w+\([^()]*\); \)|\?[^?]+(?=\)$)/m';
$str = ' this is in blue color","(Refer: \'(color:rgb(61, 142, 185); )Set the TEST VIN value\'(color:rgb(0, 0, 0); ) in document: (color:rgb(61, 142, 185); )[UserGuide_Upgrade_2020_W10_final.pdf|CB:/displayDocument/UserGuide_Upgrade_2020_W10_final.pdf?task_id=12639618&artifact_id=48569866] )';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php