Start with Frontend Frameworks
Most websites share a very similar structure. The aim of frameworks is to provide a common structure so that developers don’t have to redo it from scratch and can reuse the code provided. In this way, frameworks allow us to cut out much of the work and save a lot of time.
Another list here from Wikipedia: <a href=\\\"http://en.wikipedia.org/wiki/CSS_frameworks\\\" target=\\\"_blank\\\">CSS Frameworks</a>