A variant of my studio theme provider that uses a contextual

contextualStudioTheme.lua

--!strict

local Studio = settings().Studio

local Packages = script.Parent.Parent.Packages
local Fusion = require(Packages.Fusion)

local Contextual = Fusion.Contextual
local Computed = Fusion.Computed
local Value = Fusion.Value

local dynamicFont = Value("rbxasset://fonts/families/GothamSSm.json")
local dynamicTheme = Value(Studio.Theme :: StudioTheme)

local fontContext = Contextual(dynamicFont :: Fusion.CanBeState<string>)
local themeContext = Contextual(dynamicTheme :: Fusion.CanBeState<StudioTheme>)

local themeProvider = {}
themeProvider.ThemeContext = themeContext
themeProvider.FontContext = fontContext

type studioStyleGuideColor = Fusion.CanBeState<Enum.StudioStyleGuideColor>
type studioStyleGuideModifier = Fusion.CanBeState<Enum.StudioStyleGuideModifier>

function themeProvider:GetColor(providedColor: studioStyleGuideColor, providedModifier: studioStyleGuideModifier?): Fusion.Computed<Color3>
	local currentThemeContext = themeContext:now()
	
	return Computed(function(use)
		local currentTheme = use(currentThemeContext)
		local currentColor = use(providedColor)
		local currentModifier = use(providedModifier)
		return currentTheme:GetColor(currentColor, currentModifier)
	end)
end

type fontWeight = Fusion.CanBeState<Enum.FontWeight>
type fontStyle = Fusion.CanBeState<Enum.FontStyle>

function themeProvider:GetFont(providedWeight: fontWeight?, providedStyle: fontStyle?): Fusion.Computed<Font>
	local currentFontContext = fontContext:now()
	
	return Computed(function(use)
		local currentFont = use(currentFontContext)		
		local currentFontWeight = use(providedWeight) or Enum.FontWeight.Regular
		local currentFontStyle = use(providedStyle) or Enum.FontStyle.Normal
		return Font.new(currentFont, currentFontWeight, currentFontStyle)
	end)
end

function themeProvider:GetDark(): Fusion.Computed<boolean>
	local currentThemeContext = themeContext:now()

	return Computed(function(use)
		local currentTheme = use(currentThemeContext)
		local _, _, value = currentTheme:GetColor(Enum.StudioStyleGuideColor.MainBackground):ToHSV()
		return value <= 0.6
	end)
end

do --updates the dynamic theme to match studio's theme
	local function updateTheme()
		dynamicTheme:set(Studio.Theme)
	end
	
	local themeChangedConnection = Studio.ThemeChanged:Connect(updateTheme)
	
	local currentPlugin = script:FindFirstAncestorWhichIsA("Plugin")
	if currentPlugin then
		currentPlugin.Unloading:Once(function()
			themeChangedConnection:Disconnect()
		end)
	end
end

return themeProvider