How to edit the color of the text in chat

[Lvxye]

hello,
When a player writes in the ooc chat, the color should be grey change.
How do I do that?

Code:(serverside)

hook.Add( "PlayerSay", "ChatCommand1", function( ply, text, team )
if (string.sub( text, 1, 4 ) ) == "/ooc" then 
PrintMessage( HUD_PRINTTALK, "[OOC] " .. Entity( 1 ):SteamName() .. ":" .. string.sub( text, 5) )

return false
end
end)

Does it have to be clientside?
thx

[Trackster]

To have colored chat messaged you need it clientside