So, you’d like to get Vim to use the syntax colors from your colorscheme but you would like the background to match the color of your terminal emulator.
Surprisingly, I couldn’t find this info anywhere. But through hacking around with a colorscheme to figure out how it sets background colors, I finally found out how.
highlight Normal ctermbg=none guibg=none highlight SignColumn ctermbg=none guibg=none highlight LineNr ctermbg=none guibg=none
If you use GitGutter, you must also add this configuration line:
let g:gitgutter_override_sign_column_highlight = 0