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关于 Material Design
Material Design is a design language developed by Google in 2014. Expanding on the "cards" UI that debuted in Google Now, Material Design uses more grid-based layouts, responsive animations and transitions, padding, and depth effects such as lighting and shadows. Google announced the initial version of Material Design on June 25, 2014, at the 2014 Google I/O conference.
来源：维基百科
