setting up dark/white mode. fixed some other small things

components/ThemeToggle.tsx

@@ -0,0 +1,49 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { Sun, Moon } from "lucide-react";
+
+type Theme = "light" | "dark";
+
+export default function ThemeToggle() {
+  const [theme, setTheme] = useState<Theme>("dark");
+  const [mounted, setMounted] = useState(false);
+
+  useEffect(() => {
+    const stored = (localStorage.getItem("theme") as Theme | null) ?? "dark";
+    setTheme(stored);
+    setMounted(true);
+  }, []);
+
+  if (!mounted) return null; // prevents hydration mismatch
+
+  function toggle() {
+    const next: Theme = theme === "dark" ? "light" : "dark";
+    setTheme(next);
+    localStorage.setItem("theme", next);
+    document.documentElement.classList.toggle("dark", next === "dark");
+  }
+
+  return (
+    <button
+      type="button"
+      onClick={toggle}
+      aria-label="Toggle theme"
+      className="inline-flex items-center gap-2 rounded-md border border-zinc-700 bg-zinc-900/70 px-3 py-1.5 text-xs font-semibold text-zinc-200 hover:bg-zinc-800 transition-colors
+                 dark:border-zinc-700 dark:bg-zinc-900/70 dark:text-zinc-200
+                 border-zinc-300 bg-white text-zinc-900 hover:bg-zinc-100 dark:hover:bg-zinc-800"
+    >
+      {theme === "dark" ? (
+        <>
+          <Sun className="h-4 w-4" />
+          Light
+        </>
+      ) : (
+        <>
+          <Moon className="h-4 w-4" />
+          Dark
+        </>
+      )}
+    </button>
+  );
+}