If you want to set a different background color for a specific buffer, maybe, of a specific mode, you can add a hook for that mode and do something like this:
(add-hook 'neotree-mode-hook (lambda () (setq buffer-face-mode-face `(:background "#211C1C")) (buffer-face-mode 1)))
You can also toggle
linum-mode or set the value for
right-fringe-width, they’re only affects the current buffer.
The following screenshot is the example of my setup, changing the background color for
term-mode to have a fancy look: