Change Gutenberg Blocks Width to Match Page Template

editorskit-template-block-sizes.php

<?php

//add theme support for template blocks width
add_theme_support('editorskit-template-block-sizes', array(
	'default' => array(
		'default' 	=> '700px',
		'wide' 		=> '1000px',
		'full' 		=> '1200px',
	),
	'page-templates/landing.php' => array(
		'default' 	=> '500px',
		'wide' 		=> '900px',
		'full' 		=> '1200px',
	)
));

?>