Webflow - https://www.webflow.com - Let's you build responsive sites in a web UI without code. I'm a non-technical founder and I use it for our marketing site (works across browsers, has CSS animations). Our devs have never even touched it. I've been very, very happy with it.
I took a look at this, and it seems to be aimed at designers? While I'm sure that it's a fantastic tool (also judging from the other positive comments), what if the target audience (the non-technical end-users editing the content) also can't design their way out of a wet paper box?
(Frankly, I would prefer to not even let them touch the content ...)
