Per Post CSS for Widget Content

ppc4Widget- Content

/*
Per Post Custom CSS
This bit of code will add a meta box to the bottom 
of every post and page content editor. In that box 
you can enter your CSS styling declarations and that 
specific CSS style will ONLY be loaded on that individual 
page or post. 
*/
add_action('admin_menu', 'bb_custom_css_hooks');
add_action('save_post', 'bb_save_custom_css');
add_action('wp_head','bb_insert_custom_css');
function bb_custom_css_hooks() {
  add_meta_box('custom_css', 'Custom CSS', 'custom_css_input', 'post', 'normal', 'high');
	add_meta_box('custom_css', 'Custom CSS', 'custom_css_input', 'page', 'normal', 'high');
//add metabox to builders widget content
	add_meta_box('custom_css', 'Custom CSS', 'custom_css_input', 'widget_content', 'normal', 'high');
}
function custom_css_input() {
	global $post;
	echo '<input type="hidden" name="custom_css_noncename" id="custom_css_noncename" value="'.wp_create_nonce('custom-css').'" />';
	echo '<textarea name="custom_css" id="custom_css" rows="5" cols="30" style="width:100%;">'.get_post_meta($post->ID,'_custom_css',true).'</textarea>';
}
function bb_save_custom_css($post_id) {
	if (!wp_verify_nonce($_POST['custom_css_noncename'], 'custom-css')) return $post_id;
	if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) return $post_id;
	$custom_css = $_POST['custom_css'];
	update_post_meta($post_id, '_custom_css', $custom_css);
}
function bb_insert_custom_css() {
	if (is_page() || is_single()) {
		if (have_posts()) : while (have_posts()) : the_post();
			echo '<style type="text/css">'.get_post_meta(get_the_ID(), '_custom_css', true).'</style>';
		endwhile; endif;
		rewind_posts();
	}
}