I'm using coc.nvim plugin for C++ in my vim editor, here it's showing error but its colors hurt my eyes, I've been searching for solution but still don't know how to customize the colors
To choose another background color you can use
:highlight CocFloating ctermbg=color
And to change the foreground (text) color of the error message use
:highlight CocErrorFloat ctermfg=color
where color is either a color name or a color number (generally from 0 to 15).
To read more on color values
:h cterm-colors
If you want to use a GUI for vim, you should consider using guibg and guifg arguments in addition to ctermbg and ctermfg.
guifg and guibg value is either a color name or a hex-encoded RGB value (ex. #ff0000 for red).
GUI color values can be found here
:h gui-colors