Subscribe2 how to increase the height of input fields?

The height of ’email’ input field and buttons are like 5px at the moment, how can I increase the height?

I found the code below in subscribe2.php, I tried ‘height’ , class=\”commentform\” , margin/padding , nothing works! >.<

$this->form = "<form method=\"post\" action=\"" . $url . "\"><input type=\"hidden\" name=\"ip\" value=\"" . $_SERVER['REMOTE_ADDR'] . "\" /><p>" . __('Receive Email Updates!', 'subscribe2') . "<br /><input type=\"text\" name=\"email\" value=\"" . __('Enter email address...', 'subscribe2') . "\" size=\"40\" onfocus=\"if (this.value == '" . __('Enter email address...', 'subscribe2') . "') {this.value = '';}\" onblur=\"if (this.value == '') {this.value = '" . __('Enter email address...', 'subscribe2') . "';}\" /></p><p>" . $this->input_form_action . "</p></form>\r\n";