Howdy DNers. I'm the co-author of Variance; be happy to answer any questions about it.
One of the major design goals for the product was to enable designers to create and style data graphics without having to rely on developers or mix presentation and structure in JS. Variance uses a normal HTML/CSS (or Slim, Sass, &c) web workflow, so it's easy to make style changes, set a house style for all charts, add CSS animation and hovers, and so forth.
I think I'll be playing with this to check it out. From what I can tell it looks like a great substitute for D3 until I can actually devote the weekends to learn it.