Is this a translation issue? I do not understand what you are talking about. The site features you describe do not work like you describe them.
What is the "home page"? What is the "custom banner"? What is a "sub item" on the home page? What backgrounds are you talking about?
And if your browser does settings for each subpage, this is the what your browser does. And what theme are you talking about?
The home page is itch.io. And it does not have a background. The only sub pages are either games or browse/devlogs etc. And games only have one background, depending on the developer. The other pages have none. If you talk about hover screenshots, those are two max or none when you view a game from a profile. The button to go back to the home page is the icon on the upper left. And this icon stays there. The site changes appearances depending on the screen resolutions. You can try this by resiszing the window or changing zoom.