Plugin style and script

Hello, I have problem with my plugin. In my plugin I add folder webroot/css and put it all styles .css files, and include it on code:

<?= $this->Html->css('Pp.test'); ?>

When I open plugin page styles not included and in source code styles view that:
<link rel="stylesheet" href="/pp/css/test.css"/>

and after open link http://localhost:802/pp/css/test.css
I’ve get error

Error: Test.cssController could not be found.
Error: Create the class Test.cssController below in file: src/Controller/Test.cssController.php

My route view like this:

Router::scope('/pp', ['plugin' => 'Pp'], function (RouteBuilder $routes) {
    $routes->connect('/', ['controller' => 'Pages', 'action' => 'index']);


Can you help me ?