This can be done using auto commands:
hi Normal=white guifg=white
au CmdLineEnter * hi Normal ctermfg=cyan guifg=cyan
au CmdLineLeave * hi Normal ctermfg=white guifg=white
Surprisingly, this only affects CmdLine, not everything else.
, CmdLine. CmdLineLeave , ; , , .
, vim , ctermfg guifg; , vim vi.
ModeMsg.