The following code snippet will allow you to apply the Tango Dark color scheme to the Vim’s built-in terminal and ensure that the terminal’s color scheme remains consistent, even if you change the Vim color scheme with the ‘:colorscheme’ command.

The snippet uses autocmd to ensures that the Vim terminal’s color scheme remains Tango Dark.

For more information about Vim’s built-in terminal:

• :help terminal

" Language: Vim script
" Author: James Cherti
" License: MIT
" Description: Improve the color scheme of Vim Terminal (Tango dark theme),
"              and prevent :colorscheme from changing the terminal color scheme.
" URL: https://www.jamescherti.com/vim-tango-color-scheme-vim-terminal/

" Gnome-Terminal Tango Dark
let g:terminal_ansi_colors_black = '#2E3436'
let g:terminal_ansi_colors_darkred = '#CC0000'
let g:terminal_ansi_colors_darkgreen = '#4E9A06'
let g:terminal_ansi_colors_brown = '#C4A000'
let g:terminal_ansi_colors_darkblue = '#3465A4'
let g:terminal_ansi_colors_darkmagenta = '#75507B'  " dark purple
let g:terminal_ansi_colors_darkcyan = '#06989A'  " dark turquoise
let g:terminal_ansi_colors_lightgrey = '#D3D7CF'
let g:terminal_ansi_colors_darkgrey = '#555753'
let g:terminal_ansi_colors_red = '#EF2929'
let g:terminal_ansi_colors_green = '#8AE234'
let g:terminal_ansi_colors_yellow = '#FCE94F'
let g:terminal_ansi_colors_blue = '#729FCF'
let g:terminal_ansi_colors_magenta = '#AD7FA8'  " purple
let g:terminal_ansi_colors_cyan = '#34E2E2' " turquoise
let g:terminal_ansi_colors_white = '#EEEEEC'

" Text and background: Gnome dark
let g:terminal_ctermbg = 'black'
let g:terminal_ctermfg = 'white'
let g:terminal_statuslineterm_ctermbg = 'black'
let g:terminal_statuslineterm_ctermfg = 'white'
let g:terminal_statuslinetermnc_ctermbg = 'black'
let g:terminal_statuslinetermnc_ctermfg = 'white'
let g:terminal_guibg = '#000000'
let g:terminal_guifg = '#D0CFCC'
let g:terminal_statuslineterm_guibg = g:terminal_guibg
let g:terminal_statuslineterm_guifg = g:terminal_guifg
let g:terminal_statuslinetermnc_guibg = g:terminal_guibg
let g:terminal_statuslinetermnc_guifg = g:terminal_guifg

function! SetTerminalColorScheme() abort
  if !has('terminal')
    return
  endif

  let g:terminal_ansi_colors = [
        \ g:terminal_ansi_colors_black,
        \ g:terminal_ansi_colors_darkred,
        \ g:terminal_ansi_colors_darkgreen,
        \ g:terminal_ansi_colors_brown,
        \ g:terminal_ansi_colors_darkblue,
        \ g:terminal_ansi_colors_darkmagenta,
        \ g:terminal_ansi_colors_darkcyan,
        \ g:terminal_ansi_colors_lightgrey,
        \ g:terminal_ansi_colors_darkgrey,
        \ g:terminal_ansi_colors_red,
        \ g:terminal_ansi_colors_green,
        \ g:terminal_ansi_colors_yellow,
        \ g:terminal_ansi_colors_blue,
        \ g:terminal_ansi_colors_magenta,
        \ g:terminal_ansi_colors_cyan,
        \ g:terminal_ansi_colors_white
        \ ]

  execute printf(
        \ 'highlight Terminal ctermbg=%s ctermfg=%s guibg=%s guifg=%s',
        \ g:terminal_ctermbg, g:terminal_ctermfg, g:terminal_guibg,
        \ g:terminal_guifg
        \ )
  execute printf(
        \ 'highlight StatusLineTerm ctermbg=%s ctermfg=%s guibg=%s guifg=%s',
        \ g:terminal_statuslineterm_ctermbg, g:terminal_statuslineterm_ctermfg,
        \ g:terminal_statuslineterm_guibg, g:terminal_statuslineterm_guifg
        \ )
  execute printf(
        \ 'highlight StatusLineTermNC ctermbg=%s ctermfg=%s guibg=%s guifg=%s',
        \ g:terminal_statuslinetermnc_ctermbg, g:terminal_statuslinetermnc_ctermfg,
        \ g:terminal_statuslinetermnc_guibg, g:terminal_statuslinetermnc_guifg
        \ )
endfunction

if has('terminal')
  augroup TerminalColorScheme
    autocmd!
    autocmd ColorScheme * call SetTerminalColorScheme()
    autocmd VimEnter * call SetTerminalColorScheme()
  augroup END

  call SetTerminalColorScheme()
endifCode language: Vim Script (vim)