first commit

app/components/ThemeProvider.tsx

@@ -0,0 +1,59 @@
+"use client";
+
+import React, { createContext, useContext, useEffect, useState } from "react";
+
+type Theme = "light" | "dark";
+
+interface ThemeContextType {
+  theme: Theme;
+  toggleTheme: () => void;
+}
+
+const ThemeContext = createContext<ThemeContextType>({
+  theme: "dark",
+  toggleTheme: () => {},
+});
+
+export function useTheme() {
+  return useContext(ThemeContext);
+}
+
+export function ThemeProvider({ children }: { children: React.ReactNode }) {
+  const [theme, setTheme] = useState<Theme>("dark");
+  const [mounted, setMounted] = useState(false);
+
+  useEffect(() => {
+    const stored = localStorage.getItem("chrono-theme") as Theme | null;
+    if (stored) {
+      setTheme(stored);
+    } else if (window.matchMedia("(prefers-color-scheme: light)").matches) {
+      setTheme("light");
+    }
+    setMounted(true);
+  }, []);
+
+  useEffect(() => {
+    if (!mounted) return;
+    const root = document.documentElement;
+    if (theme === "dark") {
+      root.classList.add("dark");
+    } else {
+      root.classList.remove("dark");
+    }
+    localStorage.setItem("chrono-theme", theme);
+  }, [theme, mounted]);
+
+  const toggleTheme = () => {
+    setTheme((prev) => (prev === "dark" ? "light" : "dark"));
+  };
+
+  if (!mounted) {
+    return <div style={{ visibility: "hidden" }}>{children}</div>;
+  }
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggleTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  );
+}