--- title: Remix description: Adding dark mode to your Remix app. --- ## Modify your tailwind.css file Add `:root[class~="dark"]` to your tailwind.css file. This will allow you to use the `dark` class on your html element to apply dark mode styles. ```css {2} title="app/tailwind.css" showLineNumbers .dark, :root[class~="dark"] { ...; } ``` ## Install remix-themes Start by installing `remix-themes`: ```bash npm install remix-themes ``` ## Create a session storage and theme session resolver ```tsx title="app/sessions.server.tsx" showLineNumbers import { createThemeSessionResolver } from "remix-themes" // You can default to 'development' if process.env.NODE_ENV is not set const isProduction = process.env.NODE_ENV === "production" const sessionStorage = createCookieSessionStorage({ cookie: { name: "theme", path: "/", httpOnly: true, sameSite: "lax", secrets: ["s3cr3t"], // Set domain and secure only if in production ...(isProduction ? { domain: "your-production-domain.com", secure: true } : {}), }, }) export const themeSessionResolver = createThemeSessionResolver(sessionStorage) ``` ## Set up Remix Themes Add the `ThemeProvider` to your root layout. ```tsx {1-3,6-11,15-22,25-26,28,33} title="app/root.tsx" showLineNumbers import clsx from "clsx" import { PreventFlashOnWrongTheme, ThemeProvider, useTheme } from "remix-themes" import { themeSessionResolver } from "./sessions.server" // Return the theme from the session storage using the loader export async function loader({ request }: LoaderFunctionArgs) { const { getTheme } = await themeSessionResolver(request) return { theme: getTheme(), } } // Wrap your app with ThemeProvider. // `specifiedTheme` is the stored theme in the session storage. // `themeAction` is the action name that's used to change the theme in the session storage. export default function AppWithProviders() { const data = useLoaderData() return ( ) } export function App() { const data = useLoaderData() const [theme] = useTheme() return ( ) } ``` ## Add an action route Create a file in `/routes/action.set-theme.ts`. Ensure that you pass the filename to the ThemeProvider component. This route is used to store the preferred theme in the session storage when the user changes it. ```tsx title="app/routes/action.set-theme.ts" showLineNumbers import { createThemeAction } from "remix-themes" import { themeSessionResolver } from "./sessions.server" export const action = createThemeAction(themeSessionResolver) ``` ## Add a mode toggle Place a mode toggle on your site to toggle between light and dark mode. ```tsx title="components/mode-toggle.tsx" showLineNumbers import { Moon, Sun } from "lucide-react" import { Theme, useTheme } from "remix-themes" import { Button } from "./ui/button" import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger, } from "./ui/dropdown-menu" export function ModeToggle() { const [, setTheme] = useTheme() return ( setTheme(Theme.LIGHT)}> Light setTheme(Theme.DARK)}> Dark ) } ```