I can't find the h5p-theme when using h5p-php-library

Hello,

I am integrating H5P using `php-h5p-library` in a custom PHP setup, and I have an issue regarding the `h5p-theme`.

In the CSS of some H5P content types like the accordion, I see rules referring to:

```css
.h5p-accordion .h5p-panel-button::before {
    font-family: 'h5p-theme';
    content: "\e919";
    /* … */
}
```

I understand there should be a font and CSS theme file associated with  `h5p-theme` (for example, a CSS file like `h5p-theme.css` and font files), but I cannot find:

- The CSS file for the theme  `h5p-theme`,
- The font files supporting the font family  `font-family: 'h5p-theme'`.

I have tried creating the theme on my own starting from Font Awesome 4 (4.5/4.7) fonts, defining `@font-face` and using the font family `'h5p-theme'`. With that, I get icons displayed, but the rest of the CSS styling (spacing, colors, CSS variables) does not look like the official examples shown on h5p.org when rendering the same content.

My questions are:

1. Where exactly can I find the official  tema `h5p-theme` (CSS and fonts) to use it with `php-h5p-core` in a custom integration?
2. Is there any guide or reference explaining how to properly load the full theme (CSS, fonts, variables) outside of established platforms like Moodle/WordPress/Drupal so the visual output matches h5p.org examples?
3. Is it expected that in custom integrations we have to recreate the theme starting from Font Awesome 4, or is there an official package that includes everything needed for  `h5p-theme`?

Any links to repositories, documentation, or minimal working examples (standalone PHP) showing how to load the complete theme would be greatly appreciated.

Thanks in advance.