• Use node version manager to install the compatible node version: nvm install 16.13.0

• yarn install

• yarn start

• open in browser: http://localhost:8080/

• run tests: yarn test

Do both tasks and make sure to delete the node_modules folder when zipping the project and returning it.

Look at the video added in the docs folder (docs/responsive-header-with-dark-mode.mov). Change the CSS and/or HTML of the Header component to make it responsive and have a dark mode, similarly to what is shown in the screen recording.

The user interface now gets updated with the time every 10 seconds. The time is requested from a server as the user can get extra time and also needs to be synchronized with the server time. Change the user interface logic so that the timer displayed to the user counts every second, while still requesting/synchronizing with the server every 10 seconds. Calling the api every second should not be done as this will increase the load on the server. Write some unit tests for this change.