Change the default size of the Site Logo in a Twenty Sixteen child theme

functions.php

<?php
function twentysixteen_setup() {
	/*
	 * Make theme available for translation.
	 * Translations can be filed in the /languages/ directory.
	 * If you're building a theme based on Twenty Sixteen, use a find and replace
	 * to change 'twentysixteen' to the name of your theme in all the template files
	 */
	load_theme_textdomain( 'wpcampus', get_template_directory() . '/languages' );

	// Add default posts and comments RSS feed links to head.
	add_theme_support( 'automatic-feed-links' );

	/*
	 * Let WordPress manage the document title.
	 * By adding theme support, we declare that this theme does not use a
	 * hard-coded <title> tag in the document head, and expect WordPress to
	 * provide it for us.
	 */
	add_theme_support( 'title-tag' );

	/*
	 * Enable support for custom logo.
	 *
	 *  @since Twenty Sixteen 1.2
	 */
	add_theme_support( 'custom-logo', array(
		'height'      => 240,
		'width'       => 240,
		'flex-height' => true,
        'flex-width'  => true
	) );

	/*
	 * Enable support for Post Thumbnails on posts and pages.
	 *
	 * @link http://codex.wordpress.org/Function_Reference/add_theme_support#Post_Thumbnails
	 */
	add_theme_support( 'post-thumbnails' );
	set_post_thumbnail_size( 1200, 9999 );

	// This theme uses wp_nav_menu() in two locations.
	register_nav_menus( array(
		'primary' => __( 'Primary Menu', 'wpcampus' ),
		'social'  => __( 'Social Links Menu', 'wpcampus' ),
	) );

	/*
	 * Switch default core markup for search form, comment form, and comments
	 * to output valid HTML5.
	 */
	add_theme_support( 'html5', array(
		'search-form',
		'comment-form',
		'comment-list',
		'gallery',
		'caption',
	) );

	/*
	 * Enable support for Post Formats.
	 *
	 * See: https://codex.wordpress.org/Post_Formats
	 */
	add_theme_support( 'post-formats', array(
		'aside',
		'image',
		'video',
		'quote',
		'link',
		'gallery',
		'status',
		'audio',
		'chat',
	) );

	/*
	 * This theme styles the visual editor to resemble the theme style,
	 * specifically font, colors, icons, and column width.
	 */
	add_editor_style( array( 'css/editor-style.css', twentysixteen_fonts_url() ) );

	// Indicate widget sidebars can use selective refresh in the Customizer.
	add_theme_support( 'customize-selective-refresh-widgets' );
}

style.css

.custom-logo {
    max-width: 65%;
}

@media screen and (min-width: 1240px) {
    .custom-logo {
        max-width: 50%;
    }
}