How can I change a specific font color in git?

I think Andrew's answer is not 100% accurate, color.status.updated default color is green not red. So my answer would be:

git config --global color.status.changed magenta
git config --global color.status.untracked magenta
git config --global color.diff.old magenta

git config --global color.status.updated magenta
git config --global color.status.untracked magenta
git config --global color.diff.old magenta

Substitute ”magenta” for whatever color desired. See the git-config documentation for more details.

I believe Git just uses terminal color codes... so you'd need to change your terminal's ANSI color code mappings to a different color. The method of doing this (and whether it's even possible) varies depending on the terminal.