It is impossible to imagine modern web design without CSS. With CSS3, web designers are able to rely on advanced functions such as gradients, transitions, and animations. On the other hand, CSS code becomes more complex and difficult to maintain. Less is a CSS preprocessor that extends CSS with modern programming-language concepts. Less enables you to use variables, functions, operations, and even rule or selector nesting while coding your CSS. Less helps you write CSS with the Don't Repeat Yourself (DRY) principle. The DRY principle prevents you from repeating any kind of information in your code.
This chapter will cover the following topics: