Themify Flow is a framework which allows designers, developers and you to build responsive themes within WordPress. And it is FREE!
Design responsive themes with drag & drop. It is really easy to use.
Simply drop in the layout modules, configure the options, and tada! The layout will be shown in the live preview instantly. Full control of layouts and modules.
Complete control of styling for every element on your site using the Styling panel. No CSS coding.
You can style everything with a live preview of the design. It comes with Google Fonts, color picker, image upload, and more.
Build as many custom templates as you want using the drag & drop Builder.
You can assign templates to any page views: homepage, posts, pages, categories, tags, blog, and even custom post types & taxonomies by third party plugins such as WooCommerce templates. Regardless of the main template layout, each template can have its own version of the header, sidebar, and footer.