Small improvements

I removed standard CSS from the body tag, it interferes with my styling and it is unnecessary.
Menu now hides when clicking outside the editor. I believe this is expected behaviour, I myself kept clicking outside only to note the menu never hides that way. Which is weird...
Unable to select whitespace, you can't and shouldn't apply styling to whitespace.
Clicking a button in menu now only works with the left mousebutton, this is expected and default button behaviour.

What I think should be implemented is that selected text is trimmed of whitespace at the beginning and end. So if you select "Hello " it will style "Hello" and exclude the trailing whitespace.