Go here to view the demo. Toggle the stretch features on/off using the button in the top right of the page.
The tasks are hardcoded into the state of App and the categories are imported into App, use these to display the category filter buttons.
You will need to add something else to the state of App to track which category has been selected.
All the css is included in src/App.css, just make sure your classes are correct (but don't worry about the styling too much!).