How to add custom styles to form elements in template.php file?

Ex: 

/*To add styles to form elements in template.php file*/

function theme_form_element($element, $value) {

// This is also used in the installer, pre-database setup.

$t = get_t();

$output = '<div class="form-item"';

if (!empty($element['#id'])) {

$output .= ' id="'. $element['#id'] .'-wrapper"';

}

$output .= ">\n";

$required = !empty($element['#required']) ? '<span class="form-required" title="'. $t('This field is required.') .'">* </span>' : '';

if (!empty($element['#title'])) {

$title = $element['#title'];

if (!empty($element['#id'])) {

$output .= ' <label for="'. $element['#id'] .'">'. $t('!title !required', array('!title' => filter_xss_admin($title), '!required' => $required)) ."</label>\n";

}

else {

$output .= ' <label>'. $t('!title: !required', array('!title' => filter_xss_admin($title), '!required' => $required)) ."</label>\n";

}

}

$output .= " $value\n";

if (!empty($element['#description'])) {

$output .= ' <div class="description">'. $element['#description'] ."</div>\n";

}

$output .= "</div>\n";

return $output;

}

 

/* It would be possible to add styles to individual elements*/

function theme_button($element) {

   if (isset($element['#attributes']['class'])) {

    $element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];

  }

  else {

    $element['#attributes']['class'] = 'form-'. $element['#button_type'];

  }

  return '<input type="'.(isset($element['#button_type']) ? $element['#button_type'] : "submit").'" '. (empty($element['#name']) ? '' : 'name="'. $element['#name'] .'" ') .'id="'. $element['#id'] .'" value="'. check_plain($element['#value']) .'" '. drupal_attributes($element['#attributes']) ." />\n";

}

 

 

/* For Fieldset */

function phptemplate_fieldset($element) {

  if ($element['#collapsible']) {

    drupal_add_js('misc/collapse.js');

 

    if (!isset($element['#attributes']['class'])) {

      $element['#attributes']['class'] = '';

    }

 

    $element['#attributes']['class'] .= ' collapsible';

    if ($element['#collapsed']) {

     $element['#attributes']['class'] .= ' collapsed';

    }

  }

  return '<fieldset'. drupal_attributes($element['#attributes']) .'>'. ($element['#title'] ? '<legend>'. $element['#title'] .'</legend>' : '') .'<div class="top"><div class="bottom"><div class="bottom-ornament">'. (isset($element['#description']) && $element['#description'] ? '<div class="description">'. $element['#description'] .'</div>' : '') . (!empty($element['#children']) ? $element['#children'] : '') . $element['#value'] ."</div></div></div></fieldset>\n";

}