CSS overrides not loaded on embed path - Drupal 8

I have a custom module that loads css to override the default styling like so:

function h5p_css_overrides_h5p_styles_alter(&$styles, &$libraries, $mode) {
  // Add special styles for all H5P Content
  $styles[] = (object) array(
    'path' => drupal_get_path('module', 'h5p_css_overrides') . '/h5p-global-overrides.css',
    'version' => '?ver=1',
  $libraries[] = 'h5p_css_overrides/global';

This module works properly when viewing h5p content within the site, however the CSS file here does not get loaded when the h5p is embedded.

For example, on /node/1 where the h5p content is created, the CSS overrides are in affect. However, when viewing the content at the embed path, /h5p/1/embed, the CSS is not loaded.

Any help would be greatly appreciated.