Chrome's Stylebot allows you to right click any item in the page, and automatically create a CSS rule for that element. I'd like to have the same for Firefox.
I've tried Stylish, but it adds so many annoying steps, since I have to "Inspect Element" with the default inspector, then figure it out how to call it in the CSS, then in the CSS fill everything manually …
Look at a couple of Stylebot screenshot to get an idea:
It allows you to edit stuff live and see the preview while you're editing.
It doesn't have to have all the fancy visual options as Stylebot, it's fine as long as it lets me right click an element and have that element's name be pre-filled in the CSS: if then I have to manually set the CSS property, it's fine – assuming it previews them on-the-fly.
Now, I'm pretty sure there's nothing like that or I would have found it, but asking might bring unexpected results, and in future there might be an answer.
I want to keep the changes between reloads, so just modifying the CSS in Inspect Element is not sufficient.