Use more specific class names: grouped -> btn-grouped

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Refactor scss

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
 Merge branch 'refactor_css' into 'master'

Refactor Css