Briqs, a free app designed to make it easy to create responsive web sites without writing code, is now available in the Mac App Store (http://tinyurl.com/q78vn7e). It requires Mac OS X 10.8 or higher.
Briqs offers full automatic adjustment and management via its drag and drop subsystem. The design canvas of the tool is an extended WebKit engine. The unique way the design canvas handles interactions is adapted to the requirements of the flexible floating nature of HTML elements, according to the developers of Briqs.
Design adjustments in Briqs can be made targeting all or specific device sizes. The app automatically manages all the complexity of CSS media queries for you while you design your page.
Briqs is designed with complex multi-page web projects in mind. It supports multiple background layers. For more info go to http://briqs.co .