I have knowledge about html, css and jQuery. Recently I knew about Sass and less. As they both are the stylesheet language I am little bit confused in where to use both of them as css is already there and it is also widely used in every website. So how to know where to use these (Less,Sass) in that particular field. Another doubt comes to my mind is it fine to use Sass and Less in wordpress instaed of default css. Really I am curious to know about these. Any help and suggestions will be appreciable.