I was a user of EditCSS, which was attached on the side of the window This is what i miss the most here.
(i dislike the popup that can be moved and its opacity) A neat side bar is fine.

It would allow to add/edit styles without loading every style sheet from the page opened. That was a great and simple tool saving time , you could load or save a local file.

I used it to create my style sheet and could open/save them locally and see right away the result. No need to run a whole editing program I wish we would have these basic options too . i find myself using mostly jsbin or codepen editors for those purpose instead while editing live a page for debugging i use the webtools from the browsers . Searching again to see if anything alike EditCSS came up, i found this addon and realized it was already installed . A light version able to open/save local style sheet would be great (Also not running a server - light and simple should be plenty efficient ;) ).

Thanks for reading.