Lighting is not updating from the server. How would I do this?

I want to make the lighting pulse red server-wide. Unfortunately, it doesn't seem to work in any of the places I have tried running it from (workspace, serverscriptservice, etc). What am I doing wrong?

local l = game.Lighting
local c = l.Ambient
local b = l.Brightness

c = Color3.fromRGB(255,255,0)
for count = 1, 10, 1 do
    b = b - 0.2
    wait()
end

There are no errors when I try to run it. Nor is there anything highlighted/underlined. Please help, I would be very grateful since I am bad at roblox coding.