public function nav( $nav_class = '' ) {
		echo '<ul role="tablist" class="wplibs-box__nav ' . esc_attr( $nav_class ) . '">';

		foreach ( $this->sections() as $section ) {
			echo $section->navlink(); // @WPCS: XSS OK.
		}

		echo '</ul><!-- /.wplibs-box__nav -->';
	}