I would recommend grabbing the bit of code from each font page (linked in ~esc's comment) and slip it in at the top of your style, before anything else.
So add this:
before your “::-webkit-scrollbar” selector. I know Scribbld allows linked stylesheets as I have used them before, but it might be tripping up over the fact that there isn't a .css file extension. (Don't 100% quote me on that, because it could be something totally weird and unrelated to the file extension. :/ Hard to tell sometimes.)
I know that adding the codes like I've put in the textbox here has always worked for me. I've never tried linking them externally.