In order to make the Editor toolbar buttons bigger, you need to do the following:
1. Increase the button size, which is by default 24px:
2. Replace all button background image styles, because currently they are located in a sprite image, which does not allow bigger button size (you will start seeing adjacent images in the button).
3. Modify all backgrond position styles, which are now adjusted for the current sprite and button size.
I would not say that the above procedure is easy, so an easier approach would be to zoom the buttons with CSS:
A negative side effect would be that the button icons may not look very well, because they are enlarged.
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