Preface

CSS has dramatically changed since its very first emergence, and it is continuing to evolve. In particular, the emergence of CSS3 has added many new features to CSS, including gradients and animations. Along with this are many new opportunities to build websites using only CSS and HTML. Developers are no longer dependent on techniques such as Flash and other tricks to build interactive and fancy websites.

CSS3 has played an integral role in building responsive websites, where CSS media queries have made it possible to apply some styles dependent on the width of the browser's viewport only.

Despite this improvement, CSS is inherently, at its core, a simple style sheet language that lacks some fundamental programming features such as variables, functions, and operators. The need for more maintainable CSS, especially with the explosion of complex web apps, has made CSS preprocessors such as Less a necessity in enabling us to write more readable and manageable versions without breaking cross-browser compatibilities.

Although Less cannot magically change CSS, it certainly provides us with the tools to help structure, modularize, debug, and maintain small or large CSS projects more easily. By extending CSS with variables, functions, and mixins; nesting CSS selectors; and allowing you to follow the don't repeat yourself (DRY) principle of software programming, Less behaves more like a programming language in a way that CSS never was. Despite some of the programming characteristics of Less, you should not be put off by this; by being built as a superset of CSS, its features are implemented in the CSS way and it follows W3C standards where possible. Designers and developers who are familiar with CSS will find coding in Less very natural. Because Less fixes these shortcomings of CSS, the best time to start using Less is now!

In this book, you are going to explore the Less preprocessor, most of its core, and some of its less frequently used features. Through these very easy-to-follow and practical recipes, you will learn how to write more maintainable and scalable CSS. You will explore making components and structures through reusable mixins and extends. We will also learn about frameworks that are based on Less, exploring their features and how they can be seamlessly integrated into your own projects. In addition, you will learn how to use prebuilt mixin libraries for your current or upcoming projects. Finally, you will look at debugging techniques that have been available for other preprocessors and are now available to Less through source maps. By the end of this book, you will have an extended knowledge and a good understanding of the power of Less, its libraries, and the important features it has to offer to make writing your CSS more natural, productive, and intuitive.