There isn't a binary choice between "flat design" and "skeumorphism". You can use lots of different visual cues to indicate things. I loved hearing that Window

There isn't a binary choice between "flat design" and "skeumorphism". You can use lots of different visual cues to indicate things. I loved hearing that Windows 10 was going to go 'authentically digital', but that emotion died when it became apparent that they decided that mean 'flat design'. Just because something is on a computer screen doesn't mean it has to be made of simple single-colour polygons.