I had done the Google search myself, but thank you anyways 🙂
I had no idea if the plugin would work with your theme or not, and in any case, which ones would work then.
In the mean time though, I figured out how to do it without a plugin.
I simply wrote it as a HTML document from scratch, with body, style and everything, in which I could integrate the CSS commands, that somehow got overwritten, when added to the theme’s CSS code.
In other words it works now 🙂