app/components/theme-toggle.tsx

"use client"

import * as React from "react"
import { useTheme } from "next-themes"
import { Button } from "@/components/ui/button"

export function ThemeToggle() {
  const { setTheme, theme, resolvedTheme } = useTheme()
  const [mounted, setMounted] = React.useState(false)

  React.useEffect(() => {
    setMounted(true)
  }, [])

  if (!mounted) {
    return null
  }

  const toggleTheme = () => {
    setTheme(resolvedTheme === "light" ? "dark" : "light")
  }

  return (
    <Button
      variant="outline"
      size="icon"
      onClick={toggleTheme}
      className="rounded-full fixed bottom-4 right-4 z-[9999] bg-white dark:bg-gray-800 border-gray-300 dark:border-gray-600 text-gray-700 dark:text-gray-200 hover:bg-gray-50 dark:hover:bg-gray-700 shadow-lg transition-all duration-200 hover:scale-110"
    >
      {resolvedTheme === "light" ? (
        <MoonIcon className="h-[1.2rem] w-[1.2rem] transition-all duration-200" />
      ) : (
        <SunIcon className="h-[1.2rem] w-[1.2rem] transition-all duration-200" />
      )}
      <span className="sr-only">Toggle theme</span>
    </Button>
  )
}

function SunIcon(props: React.SVGProps<SVGSVGElement>) {
  return (
    <svg
      {...props}
      xmlns="http://www.w3.org/2000/svg"
      width="24"
      height="24"
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="2"
      strokeLinecap="round"
      strokeLinejoin="round"
    >
      <circle cx="12" cy="12" r="4" />
      <path d="M12 2v2" />
      <path d="M12 20v2" />
      <path d="m4.93 4.93 1.41 1.41" />
      <path d="m17.66 17.66 1.41 1.41" />
      <path d="M2 12h2" />
      <path d="M20 12h2" />
      <path d="m6.34 17.66-1.41 1.41" />
      <path d="m19.07 4.93-1.41 1.41" />
    </svg>
  )
}

function MoonIcon(props: React.SVGProps<SVGSVGElement>) {
  return (
    <svg
      {...props}
      xmlns="http://www.w3.org/2000/svg"
      width="24"
      height="24"
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="2"
      strokeLinecap="round"
      strokeLinejoin="round"
    >
      <path d="M12 3a6 6 0 0 0 9 9 9 9 0 1 1-9-9Z" />
    </svg>
  )
}