As a web developer you are aware that today's design and development cover a range of devices and platforms: mobile, tablets, responsive web, desktop apps.
To deal with all these, you have to leverage CSS frameworks or toolkits such as Twitter Bootstrap, and most of the time you struggle to achieve the results you desire.
Find out how you can build applications that comply with the new Salesforce Lightning look and feel without writing any CSS with the new Lightning Design System, a whole new way to build pixel perfect apps.