Switch Between Light and Dark

# Introduction

In this challenge, we will be using React's Context API and the useContext Hook to create a dark mode theme switcher for a web page. The challenge involves completing the code in the provided `ThemeContext.js` file and wrapping the `App` component with the `ContextProvider`. Additionally, code needs to be added in both `App.js` and `Card.js` using the useContext Hook to implement the functionality. When completed, clicking the "Dark Mode" button should change the theme color of both the card and the background.