message: docs: add mention to CSS styles for hero-detail
  PR Close
diff: @@ -470,6 +470,9 @@ Refresh the browser and start clicking.
  Users can navigate around the app, from the dashboard to hero details and back,
  from heroes list to the mini detail to the hero details and back to the heroes again.
  +The details will look better when you add the private CSS styles to `hero-detail.component.css`
  +as listed in one of the ["final code review"](#final-code-review) tabs below.
  +
  ## Final code review
  Here are the code files discussed on this page.
  