> CSS does everything Flash once did

Tell me you never used Flash by not telling me you've never used flash.

Flash's USP and core value proposition was the (IMO) fantastic IDE that you used to create flash apps and animations. It was exactly as technical as you needed it to be. As you upskilled you could do more things, but more importantly do the same things more elegantly. In stead of a manual animation you could script it out in AS3. I loved it and I'm really sad that I only entered the professional workforce as Flash was on it's way out.