public function header() {

		/**
		 * Filter the custom header args.
		 *
		 * @since 1.0.0
		 *
		 * @var array
		 */
		$args = (array) apply_filters( 'rock_custom_header_args',
			array(
				'default-text-color' => $this->get_default_color( 'header_textcolor', 'default' ),
				'width'              => 2400,
				'height'             => 1300,
				'flex-height'        => true,
				'wp-head-callback'   => array( $this, 'header_css' ),
			)
		);

		add_theme_support( 'custom-header', $args );

		/**
		 * Filter the default hero images.
		 *
		 * @var array
		 */
		$defaults = (array) apply_filters( 'rock_default_hero_images',
			array(
				'default' => array(
					'url'           => 'assets/images/hero.jpg',
					'thumbnail_url' => 'assets/images/hero-thumbnail.jpg',
				),
			)
		);

		foreach ( $defaults as $name => &$args ) {

			$path = trailingslashit( get_stylesheet_directory() );
			$url  = trailingslashit( get_stylesheet_directory_uri() );

			if ( ! file_exists( $path . $args['url'] ) ) {

				unset( $defaults[ $name ] );

				continue;

			}

			$args['url']           = $url . $args['url'];
			$args['thumbnail_url'] = file_exists( $path . $args['thumbnail_url'] ) ? $url . $args['thumbnail_url'] : $args['url'];

		}

		if ( $defaults ) {

			register_default_headers( $defaults );

		}

	}