The --user-style-sheet tag doesn't seem to be working, even when escaping the url. This isn't a real stylesheet, but for example, [...]&--user-style-sheet=http%3a%2f%2fexample.com%2fstyles%2fstyle.css&[...] does not work, even if http://example.com/styles/style.css is a functional stylesheet

I was hoping to use this as a temporary workaround for the letter-spacing property not working with negative values (e.g. letter-spacing:-3px).