A stateful component is always a class component because functional components can't maintain state by definition. Changed a line to better reflect that.
Added that the Sass import statement doesn't need the file extension like it doesn't need the underscore.
This helps beginners to better understand the concept and avoid confusion.
* Minor rephrasing of the lesson's description
Since we already said in the last lesson that bootstraps col-xs-* classes can be used on all form elements it sounds silly to repeat the exact same phrase in this lesson too.
* Corrections to conform to style guide
1- Changed use of passive voice to active voice.
2- Changed use of first person to second person.
* Moved challenge instruction to Instructions section
kevindelshandJaka Kranjc
