custom css add in wordpress

// this is for only custom css for wordpress // call this code into your functions.php

<?php
/* custom css for wordpress*/

if (!defined('ABSPATH')) die ('No direct access allowed');

if(!class_exists('Wpacc'))
{
    class Wpacc
    {
		private $options;

        public function __construct() {
            add_action('admin_menu', array($this, 'add_menu'));
        	add_action( 'admin_init', array( $this, 'init_settings' ) );
			add_action( 'add_meta_boxes', array($this, 'add_meta_box' ) );
			add_action( 'save_post', array( $this, 'single_save' ) );
			add_action('init', array($this, 'init'));
			add_filter('query_vars', array($this, 'add_wp_var'));
			add_action( 'wp_enqueue_scripts', array($this, 'add_custom_css'), 999 );
			add_action('wp_head', array($this, 'single_custom_css'));
        }

		public function init() {
			load_plugin_textdomain( 'wp-add-custom-css', false, dirname( plugin_basename( __FILE__ ) ) . '/languages' );
		}

		public static function uninstall() {
			self::delete_options();
			self::delete_custom_meta();
        }

		public function add_meta_box( $post_type ) {
			$post_types = array('post', 'page');
            	if ( in_array( $post_type, $post_types )) {
					add_meta_box('wp_add_custom_css', __( 'Custom CSS', 'wp-add-custom-css' ), array( $this, 'render_meta_box_content' ), $post_type, 'advanced', 'high');
				}
		}

		public function single_save( $post_id ) {
			if ( ! isset( $_POST['wp_add_custom_css_box_nonce'] ) || ! wp_verify_nonce( $_POST['wp_add_custom_css_box_nonce'], 'single_add_custom_css_box' ) ) {
				return;
			}
			if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
				return;
			}
			if ( 'page' == $_POST['post_type'] ) {
				if ( ! current_user_can( 'edit_page', $post_id ) )
					return;
			} else {
				if ( ! current_user_can( 'edit_post', $post_id ) )
					return;
			}

			$single_custom_css = sanitize_text_field( $_POST['single_custom_css'] );
			update_post_meta( $post_id, '_single_add_custom_css', $single_custom_css );
		}

		public function render_meta_box_content( $post ) {
			wp_nonce_field( 'single_add_custom_css_box', 'wp_add_custom_css_box_nonce' );
	  		$single_custom_css = get_post_meta( $post->ID, '_single_add_custom_css', true );
	  		echo '<p>'.  __( 'Add custom CSS rules for this ' . $post->post_type, 'wp-add-custom-css' ) . '</p> ';
			echo '<textarea id="single_custom_css" name="single_custom_css" style="min-height:200px;min-width:700px">' . esc_attr( $single_custom_css ) . '</textarea>';
		}

		public function add_menu() {
			global $wpacc_settings_page;
			$wpacc_settings_page = add_menu_page(' Add Custom CSS', 'Add Custom CSS', 'manage_options', 'wp-add-custom-css_settings', array($this, 'create_settings_page'), plugin_dir_url( __FILE__ ) . '/icon.png');
		}

		public function create_settings_page() {
			$this->options = get_option( 'wpacc_settings' );
			?>
			<div class="wrap">
                <h2><?php echo __(' Add Custom CSS', 'wp-add-custom-css'); ?></h2>
                <form id="worpress_custom_css_form" method="post" action="options.php">
                <?php settings_fields( 'wpacc_group' ); ?>
                <?php do_settings_sections( 'wp-add-custom-css_settings' ); ?>
				<?php submit_button( __('Save', 'wp-add-custom-css') ); ?>
				</form>
				<h3><?php echo __(''); ?></h3>
				<ul>
					<li>
						Add Your Custom Css And Save
					</li>
				</ul>
			</div>
            <?php
		}

		public function print_section_info() {
        	echo __('Write here the CSS rules you want to apply to the whole website.', 'wp-add-custom-css');
    	}

		public function main_css_input() {
        	printf(
            	'<textarea name="wpacc_settings[main_custom_style]" style="min-height:300px;min-width:700px;">%s</textarea>',
            	isset( $this->options['main_custom_style'] ) ? esc_attr( $this->options['main_custom_style'] ) : ''
        	);
    	}

		public function init_settings() {
			register_setting(
				'wpacc_group',
				'wpacc_settings'
			);
			add_settings_section(
            	'wpacc_main_style',
            	'Main CSS',
            	array( $this, 'print_section_info' ),
            	'wp-add-custom-css_settings'
        	);
        	add_settings_field(
            	'main_custom_style',
            	'CSS rules',
            	array( $this, 'main_css_input' ),
            	'wp-add-custom-css_settings',
            	'wpacc_main_style'
        	);
		}

		public function delete_options() {
			unregister_setting(
				'wpacc_group',
				'wpacc_settings'
			);
			delete_option('wpacc_settings');
		}

		public function delete_custom_meta() {
			delete_post_meta_by_key('_single_add_custom_css');
		}

		public static function add_wp_var($public_query_vars) {
    		$public_query_vars[] = 'display_custom_css';
    		return $public_query_vars;
		}

		public static function display_custom_css(){
    		$display_css = get_query_var('display_custom_css');
    		if ($display_css == 'css'){
				include_once (plugin_dir_path( __FILE__ ) . '/custom-css.php');
        		exit;
    		}
		}

		public function add_custom_css() {
			$this->options = get_option( 'wpacc_settings' );
			if ( isset($this->options['main_custom_style']) && $this->options['main_custom_style'] != '') {
				wp_register_style( 'wp-add-custom-css', get_bloginfo('url') . '?display_custom_css=css' );
				wp_enqueue_style( 'wp-add-custom-css' );
			}
		}

		public function single_custom_css() {
			if ( is_single() || is_page() ) {
				global $post;
				$single_custom_css = get_post_meta( $post->ID, '_single_add_custom_css', true );
				if ( $single_custom_css !== '' ) {
					$output = "<style type=\"text/css\">" . $single_custom_css . "</style>\n";
				}
				echo $output;
			}
		}


    }
}

if(class_exists('Wpacc')) {
	add_action('template_redirect', array('Wpacc', 'display_custom_css'));
	register_uninstall_hook(__FILE__, array('Wpacc', 'uninstall'));
	$wpacc = new Wpacc();
}

if(isset($wpacc)) {
    function wpacc_settings_link($links) {
        $settings_link = '<a href="admin.php?page=wp-add-custom-css_settings">' . __('Settings', 'wp-add-custom-css') . '</a>';
        array_unshift($links, $settings_link);
        return $links;
    }
    add_filter('plugin_action_links_' . plugin_basename(__FILE__), 'wpacc_settings_link');
}

?>


<?php
header("Content-type: text/css");
$custom_css = get_option('wpacc_settings');
$custom_css = wp_kses( $custom_css['main_custom_style'], array( '\'', '\"' ) );
echo $custom_css;
?>