Responsive front end build and style guide using mobile and desktop PSDs (HTML5/SASS)

This is a job to take a PSD for desktop/tablet and mobile and do the front end build and formulate a style guide/UI kit. It must be build as responsive/adaptive in a lean way with a focus on performance and optimised for all major mobile, tablet and desktop screen sizes. The PSD will simply be a static site - but assets should be optimised for high performance/use on a CDN. SASS should be used, and a style guide/UI kit should also be created from the PSD. This is very important. The final deliverable is - fully responsive/adaptive and pixel perfect high performance (high YSlow grade/minified, efficient) version of the PSDs supplied, and a style guide and UI kit. Use of CSS/JavaScript should be used to enhance the UI and provide a slick experience when the user interacts with various elements. Please include a link to your portfolio of responsive / adaptive front end development work to be considered. Background: This work is for the MVP of an exciting new start up in the news space which is effectively a brand new news aggregator that uses machine learning to determine the very best stories to present to the user in any given category of news. With user feedback/up voting and down voting to continually improve results, and the ability to sort by positive/negative sentiment articles, or quick reads, in depth articles - we have ambitions to become the go to place for all news, and eventually discussion, debate around a given topic that you're interested in. We are a bootstrapped startup and all currently work as volunteers alongside our full time jobs, though we have had significant interest from sponsors, advertisers and investors. We are looking for a lead front end developer long term - so this initial job, if done to a very high quality, may well progress in to a full time co founder role if that's what you'd like!