For generations, mankind (and probably really smart dolphins) have styled their HTML content using CSS. Things were good. With CSS, you had a good separation between the content and the presentation. The selector syntax gave you a lot of flexibility in choosing which elements to style and which ones to skip. You couldn't even find too many issues to hate the whole cascading thing that CSS is all about.
This is a companion discussion topic for the original entry at https://www.kirupa.com/react/styling_in_react.htm
