tatable = tatable or {}
tatable["theme1"] = {
	["background"] = Color(70, 70, 70),
	["blue"] = Color(155, 155, 155),
}

function tatable:GetColor(colorname)
	local color = tatable[tonthemejesuppose][colorname]
	return color
end

-- pour utiliser

tatable:GetColor("background")

-- Output:
-- Color(70, 70, 70)