better-auth/docs/components/theme-toggler.tsx

"use client";

import { Moon, MoonIcon, Sun } from "lucide-react";
import { useTheme } from "next-themes";
import * as React from "react";
import { Button } from "@/components/ui/button";
import {
	DropdownMenu,
	DropdownMenuContent,
	DropdownMenuItem,
	DropdownMenuTrigger,
} from "@/components/ui/dropdown-menu";

export function ThemeToggle() {
	const { setTheme } = useTheme();

	return (
		<DropdownMenu>
			<DropdownMenuTrigger asChild>
				<Button
					variant="ghost"
					size="icon"
					className="border-l ring-0 rounded-none h-14 w-14 hidden md:flex shrink-0"
				>
					<Sun className="h-[1.2rem] w-[1.2rem] rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0" />
					<Moon className="absolute h-[1.2rem] w-[1.2rem] rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100" />
					<span className="sr-only">Toggle theme</span>
				</Button>
			</DropdownMenuTrigger>
			<DropdownMenuContent align="end">
				<DropdownMenuItem onClick={() => setTheme("light")}>
					Light
				</DropdownMenuItem>
				<DropdownMenuItem onClick={() => setTheme("dark")}>
					Dark
				</DropdownMenuItem>
				<DropdownMenuItem onClick={() => setTheme("system")}>
					System
				</DropdownMenuItem>
			</DropdownMenuContent>
		</DropdownMenu>
	);
}
export function MobileThemeToggle() {
	const { theme, setTheme } = useTheme();
	return (
		<div className="block md:hidden">
			<Button
				variant="ghost"
				size="icon"
				onClick={() => setTheme(theme === "light" ? "dark" : "light")}
			>
				<Sun className="h-4 w-4 dark:hidden" color="#000" />
				<Moon className="hidden h-4 w-4 dark:block" />
				<span className="sr-only">Toggle theme</span>
			</Button>
		</div>
	);
}