FastMindMap (https://fastmindmap.innovationgear.com) allows adding on the board the so-called 'floating topics', and later you can build hierarchical or parallel relations between the topics with drag-and-drop. (I'm the developer).
>> A similar tool got shown here on HN...a visual tool to edit CSS is a) so handy but b) really hard to build because it's not programmatically obvious which file to make updates too...
Can you point me to the post so that I can study more details?
As mentioned about, the idea of my http://liveditor.com is not to edit the css for you but points you to the line of the css file so that you can edit the styles in the code editor and see the result instantly.
First, congrats to your new project!
Secondly, although it's not for react, but that's exactly the same reason why I have developed http://liveditor.com some years ago! The idea was that the css inspector/tweaker and the code editor should be combined together and working together seamlessly.
PS, I know the software might have some little issues but I'm going to update it soon ;)