import { useEffect, useState } from "react"; export type ThemeKey = "a" | "b" | "c" | "d" | "e"; export function useTheme() { const [theme, setTheme] = useState(() => { const saved = (typeof window !== "undefined" && localStorage.getItem("theme")) as ThemeKey | null; return saved ?? "a"; }); useEffect(() => { document.documentElement.setAttribute("data-theme", theme); localStorage.setItem("theme", theme); }, [theme]); return { theme, setTheme }; }