Add light/dark mode with toggle, fix all theme-aware text colors

app/components/ThemeProvider.tsx

@@ -0,0 +1,55 @@
+"use client"
+
+import { createContext, useContext, useEffect, useState } from "react"
+
+type Theme = "light" | "dark"
+
+interface ThemeContextValue {
+  theme: Theme
+  toggle: () => void
+}
+
+const ThemeContext = createContext<ThemeContextValue>({
+  theme: "dark",
+  toggle: () => {},
+})
+
+export function useTheme() {
+  return useContext(ThemeContext)
+}
+
+export default function ThemeProvider({ children }: { children: React.ReactNode }) {
+  const [theme, setTheme] = useState<Theme>("dark")
+  const [mounted, setMounted] = useState(false)
+
+  useEffect(() => {
+    // Read from localStorage, fall back to system preference
+    const stored = localStorage.getItem("food-theme") as Theme | null
+    if (stored === "light" || stored === "dark") {
+      setTheme(stored)
+    } else {
+      const prefersDark = window.matchMedia("(prefers-color-scheme: dark)").matches
+      setTheme(prefersDark ? "dark" : "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("food-theme", theme)
+  }, [theme, mounted])
+
+  const toggle = () => setTheme((t) => (t === "dark" ? "light" : "dark"))
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggle }}>
+      {children}
+    </ThemeContext.Provider>
+  )
+}