Enqueue css for a custom post_type in edit.php

gistfile1.aw

<?php

add_action( 'load-edit.php', 'myplugin_setup_edit_screen' );

function myplugin_setup_edit_screen() {
	$screen = get_current_screen();
	if ( 'my_post_type' != $screen->post_type ) {
		return;
	}
	add_action( 'admin_print_styles', 'myplugin_edit_screen_css' );
}

function myplugin_edit_screen_css() {
	wp_enqueue_style( 'myplugin_edit_screen' );
}

Most excellent. Thanks!