WP_Customize_Widgets::print_preview_css()

Source

File: wp-includes/class-wp-customize-widgets.php

public function print_preview_css() {
		?>
		<style>
		.widget-customizer-highlighted-widget {
			outline: none;
			-webkit-box-shadow: 0 0 2px rgba(30, 140, 190, 0.8);
			box-shadow: 0 0 2px rgba(30, 140, 190, 0.8);
			position: relative;
			z-index: 1;
		}
		</style>
		<?php
	}