On a relative scale compared to other Programming Tasks (overall) it falls under easy. And to be honest it gets easier as time goes on. You got so many Frameworks and Tools nowadays and the really strange thing is that they move towards getting directly into the Plattform. Example variables in CSS (potentially more) could outdate SASS and LESS unless there are still features like Mixins etc. that dont get built in into the Plattform.
Often find myself thinking what do I actually choose now to make this specific Website its really a lot to choose from xD