When content get loaded through ajax, neither theme.css or js get applied. Below is code snippet,

controller

    $twig = Drupal::service('twig');         $twigFilePath = drupal_get_path('module', 'mythemename') . '/templates/test.html.twig';         $template =  $twig->loadTemplate($twigFilePath);       $markup = $template->render(array('gainerList' => $gainerList, 'loseList' => $looserList));          $build = array(             '#type' => 'markup',             '#markup' => $markup,             '#attached' => array(                 'css' => array(                     drupal_get_path('themes', 'mythemename') . '/css/theme.css'                 )             )         );         return new Response(render($build)); 

Is there any issue with above code?

Also below testing code does not hide the second

.

 $build = array(             '#type' => 'markup',             '#markup' => '<p>Demo text content</p> <p style="display:none">Demo text content</p>',         );         return new Response(render($build)); 

Js file code snippet:

(function ($, Drupal) {   'use strict';    Drupal.behaviors.company = {     attach: function(context, settings) {         $.ajax({                 url: "get-top-performing-fund",                 type: 'GET',                 success:function(data, error){                     console.log(data);                     $('#topPerforming').html();                     $('#topPerforming').html(data);                 }         });     } } })(jQuery, Drupal);