Ditch Custom CSS for Bootstrap

We can clean up our code and make our Cat Photo App look more conventional by using Bootstrap's built-in styles instead of the custom styles we created earlier. Don't worry - there will be plenty of time to customize our CSS later. Delete the `.red-text`, `p`, and `.smaller-image` CSS declarations from your `style` element so that the only declarations left in your `style` element are `h2` and `thick-green-border`. Then delete the `p` element that contains a dead link. Then remove the `red-text` class from your `h2` element and replace it with the `text-primary` Bootstrap class. Finally, remove the `smaller-image` class from your first `img` element and replace it with the `img-responsive` class.