Reversing a white-on-black theme and vice versa is one of the easier things for semi-literate sub-programmers to do. Likewise, turning fixed structure-widths into percentages takes more attention, but is still a 'plodding' thing to do. The style sheet for the demo is "a.css". "background-color" is easy to find & change. "color" changes the text.

It's a 94k file, verbose & voluminous, though not as outlandish as it can get. But it might be a couple hundred pages, in the editor.

You can save a webpage locally, doctor its CSS file (change colors), then when you pull up the saved page, you see it with your mods.

The problem here isn't the abnormal colors or structural arrangements. Those will be in the style sheet (which we have). The problem is we don't have any of the other theme-files.