Getting raw content with css classes injected but without css code #515

I'm querying pages and getting the response I want, but apparently I can't get the styles that are being applied to the page I created through the wordpress CMS. The background of the paragraph I created is vivid-red, but styles are not being applied when fetching the page and I was wondering if there is a way to fetch the css that's being applied to a resource (page, content, post, etc)

This is how the content is shown in the Wordpress editor.

This is how is shown when rendering the content when querying the page.