Theme Design Similar to learn.wordpress.com

I am designing a new elearning website for a school group and I would like to design something very simple and easy to use like the website http://learn.wordpress.com/

Does anybody know of a simple, clean, responsive theme that is similar to that website?

I don’t need any fluff. i.e., no theme framework, no page builder, no built-in seo. Just a very clean, responsive theme like many of the newer designs on the WordPress.com support pages.