src/context/ThemeContext.jsx

import { createContext, useContext, useState, useEffect } from "react";

const ThemeContext = createContext();

export function useTheme() {
  return useContext(ThemeContext);
}

export function ThemeProvider({ children }) {
  const [isDark, setIsDark] = useState(() => {
    const saved = localStorage.getItem("theme");
    return saved ? saved === "dark" : true; // default to dark mode
  });

  useEffect(() => {
    if (isDark) {
      document.documentElement.classList.add("dark");
      document.documentElement.classList.remove("light");
      localStorage.setItem("theme", "dark");
    } else {
      document.documentElement.classList.add("light");
      document.documentElement.classList.remove("dark");
      localStorage.setItem("theme", "light");
    }
  }, [isDark]);

  const toggleTheme = () => setIsDark((prev) => !prev);

  return (
    <ThemeContext.Provider value={{ isDark, toggleTheme }}>
      {children}
    </ThemeContext.Provider>
  );
}