import React, { useState } from "react";import "./styles.css";
export default function App() {
const [isActive, setActive] = useState("false");
const handleToggle = () => {
setActive(!isActive); };
return (
<div className={isActive ? "app" : null}> <h1>Hello react</h1>
<button onClick={handleToggle}>Toggle class</button> </div>
);
}