Emulate reduced transparency in Polypane 16

[pankajparashar]

I'm not sure, if I am using this correctly, but reduced-transparency emulation doesn't appear to be working in Polypane 16. Same Pen on Chrome works fine.

/cc @Kilian

[Kilian]

Polypane doesn't (yet) reach into subframes (like iframes) and the way chromium works is that you need to set emulation on each frame separately.

Codepen demos always show in an iframe so that's why it looks like it doesn't do anything, but it works for people applying reduced transparency to their own sites.

[pankajparashar]

Thanks! very insightful.