Hi inkedkoi,
You can follow this tutorial to modify the radio button (apply these changes to the CSS section of your template):
https://viralpatel.net/blogs/css-radio-button-checkbox-background/
Next, edit inc/yop_poll_model.php and in answer_replace_callback functions replace
$temp_string = str_ireplace( '%POLL-ANSWER-CHECK-INPUT%', '<input type="radio" checked="checked" value="' . $answer['id'] . '" name="yop_poll_answer" id="yop-poll-answer-' . $poll_id . $unique_id . '-' . $answer['id'] . '" />', $m[5] );
(approximately on line 3461) with
$temp_string = str_ireplace( '%POLL-ANSWER-CHECK-INPUT%', '<input type="radio" checked="checked" value="' . $answer['id'] . '" name="yop_poll_answer" id="yop-poll-answer-' . $poll_id . $unique_id . '-' . $answer['id'] . '" onclick="jQuery( \'#yop_poll_vote-button-' . $poll_id . $unique_id . '\' ).click();" />', $m[5] );
and
$temp_string = str_ireplace( '%POLL-ANSWER-CHECK-INPUT%', '<input type="radio" value="' . $answer['id'] . '" name="yop_poll_answer" id="yop-poll-answer-' . $poll_id . $unique_id . '-' . $answer['id'] . '" />', $m[5] );
(approximately on line 3464) with
$temp_string = str_ireplace( '%POLL-ANSWER-CHECK-INPUT%', '<input type="radio" value="' . $answer['id'] . '" name="yop_poll_answer" id="yop-poll-answer-' . $poll_id . $unique_id . '-' . $answer['id'] . '" onclick="jQuery( \'#yop_poll_vote-button-' . $poll_id . $unique_id .'\' ).click();" />', $m[5] );
Please note that these changes will apply on all your polls.
Regards,
YOP Team