What options are there in Tailwind CSS for applying styles to the custom classes of a pre-built component?

I have a text editor in a MERN project where I am trying to change the z-index (and color eventually) of parts of its UI and cannot find a method to do so that makes me happy.

There is an obvious solution, accessing the classes with their selector in your stylesheet:

@layer utilities {
    .tox.tox-silver-sink.tox-tinymce-aux {
        z-index: 100000 !important;
    }
}

To me though, having the styles in a different file and using traditional CSS kind of defeats the main purpose of using Tailwind.

Are there any options out there to avoid that issue and keep all the styles to the className of the component?