book title in the header should probably be axo-orange

That's the style our blog uses, but currently it's just axo-pink since we set all headings to that.

I didn't bother because probably that *should* be set [in chrome.css](https://github.com/axodotdev/axomdbook/blob/f5e437641a9f0b67f4f97800b22f85fd7ffbd8d8/theme/css/chrome.css), and so I'd have to un-delete that file to start overriding it?

Start with theme/css/chrome.css, which the issue identifies as the likely place for the style override, and inspect how heading colors are currently defined. The work is done when the book title in the header uses axo-orange while the other headings retain axo-pink; verify the rendered theme after deciding whether that file must be restored.

Written by the indexing model from the issue text.