Coloring just one note in a chord

[DoubleFelix]

I have a basic staff defined like so:

\version "2.22.2"
\language "english"
\new Staff {
\key c \major
\clef treble
\numericTimeSignature
<
f'
g'
d'
>1
\bar "|."
}

I want to make the g' note head colored in green, but if I try this, I get
syntax errors about an unexpected \override:
\override NoteHead.color = SeaGreen
\override Stem.color = SeaGreen
g'
\revert NoteHead.color
\revert Stem.color

What am I doing wrong?

Thanks,
Felix