Added dark and light theme

Added navbar

app/contexts/ThemeContext.js

@@ -0,0 +1,32 @@
+"use client";
+
+import { createContext, useContext, useState, useEffect } from "react";
+
+const ThemeContext = createContext();
+
+export function ThemeProvider({ children }) {
+  const [theme, setTheme] = useState("light");
+
+  useEffect(() => {
+    const stored = localStorage.getItem("theme");
+    if (stored === "dark" || (!stored && window.matchMedia("(prefers-color-scheme: dark)").matches)) {
+      setTheme("dark");
+      document.documentElement.classList.add("dark");
+    }
+  }, []);
+
+  const toggleTheme = () => {
+    const next = theme === "light" ? "dark" : "light";
+    setTheme(next);
+    document.documentElement.classList.toggle("dark", next === "dark");
+    localStorage.setItem("theme", next);
+  };
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggleTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  );
+}
+
+export const useTheme = () => useContext(ThemeContext);