CSS is one of the key cornerstones of modern web design. It’s the reason you don’t see the web as a collection of boring text documents, instead allowing you to witness it in its full glory.

But while CSS might be the essential style sheet language, it does have its limits when used on its own.

For designers who need to get maximum functionality from our web hosting or WordPress packages, CSS preprocessors are a must-have tool. CSS preprocessors, like the incredibly useful Sass (more on this below), help to create efficient and streamlined code that’s far simpler to maintain than standard code.

And if you’re a developer who’s planning on tackling more complex web projects, like building an entire website, having knowledge of CSS preprocessors is an essential requirement to make the process a whole lot easier.

In this guide, we’ll explore what CSS is, what it’s used for, what a CSS preprocessor is, and how it works, as well as how to set one up with Sass.

What is CSS and what does CSS do?

Before we start exploring the hidden world of CSS preprocessors, it’s important to have a firm grasp of what CSS is and its fundamentals.

CSS stands for Cascading Style Sheets and is one of the original style sheet languages.

As for what CSS does; it allows a user to set the presentation and style of text documents written in a markup language like HTML. But CSS isn’t just compatible with HTML - it can also be used to present XHTML, plain XML, SVG, and even XUL.

What is CSS used for?

CSS is most commonly used to format how HTML elements should be displayed on web pages. There’s a classic metaphor used to help represent the relationship between CSS and HTML, and that’s the human body.

If HTML is the skeleton, the core content and structure of a webpage, then CSS is the skin – the visual component layered on top to make everything look nice.

Basically, without CSS, web browsers would just render HTML as plain text, which, let’s face it, isn’t very interesting to look at. Instead, CSS lets us see all the colours, fonts, layouts, and images that define the web as we know it. It’s incredibly useful and used by many online services, like the ever-popular WordPress.

All of this hints at the key principle surrounding the use of CSS: the separation of the page’s presentation from its actual content.

With the ability to apply a single style sheet to multiple pages and get consistent results, CSS enables a modular approach to a page’s individual visual elements, reducing complexity and saving time. This can greatly simplify design tasks that often involve several developers working in tandem across various web formats.

All this makes CSS an essential component of web design as a whole, but it also raises the question: if regular CSS is so great, why even use a CSS preprocessor?

What is a CSS preprocessor?

A CSS preprocessor is essentially a new scripting language that offers a variety of presentation features not typically available with standard CSS. After being written, a CSS preprocessor script can be compiled into your regular CSS code to render pages as normal.

A CSS preprocessor can’t fundamentally change the capabilities of CSS as a whole – the CSS preprocessor script has to be converted to CSS after all – but it does increase its overall functionality.

There are a number of key features that you’d typically expect to be present in a modern language that are missing from the venerable CSS. However, you can use a CSS preprocessor to implement these with minimal issues.

What are the benefits of using a CSS preprocessor

Using a CSS preprocessor offers tons of advantages that can greatly enhance your web development workflow and the overall quality of your stylesheets – no matter your skill level. Here are some of the key benefits:

1. Define variables

CSS preprocessors allow you to define variables that can store values like colours, fonts, font sizes, or any other CSS property. This makes it easy to maintain consistency throughout your stylesheets and update values across multiple files by changing the variable in just one place.

2. CSS nesting

With CSS preprocessors, you can nest selectors inside one another, mimicking the hierarchical structure of HTML. This improves code organisation and readability, as the nesting reflects the relationship between elements on the page.

3. Utilise mixins

Mixins are reusable blocks of CSS rules that can be included in other selectors. They promote code reuse and help maintain consistent styles across your project. Mixins can even accept parameters, making them highly flexible.

4. Functions

CSS preprocessors provide built-in functions that extend the capabilities of CSS. These functions can perform operations like colour manipulation, mathematical calculations, or string manipulation, enabling more complex and dynamic styling.

5. Organises code

Preprocessors allow you to split your CSS into multiple files, each containing styles for a specific component or section of your website. This modular approach makes it easier to manage and maintain large codebases, as well as collaborate with other team members who may work on this code.

6. Easy to maintain

With features like variables, mixins, and nesting, CSS preprocessors make it much easier to update and maintain your stylesheets. Changes can be made in a centralised location and automatically propagated throughout your project, reducing the risk of inconsistencies and errors.

7. Cross-browser compatibility

Many CSS preprocessors provide built-in support for vendor prefixes, which are required for certain CSS properties to work consistently across different browsers on Windows, Linux and Mac OS. This can save you time and effort in ensuring cross-browser compatibility.

What is Sass?

Sass stands for the impressive-sounding Syntactically Awesome Style Sheets, and is written using Ruby. It’s hands down one of the most popular CSS preprocessors currently available.

The actual language used by Sass is called SassScript. There are technically two types of Sass syntaxes: Sass and SCSS, or Sassy CSS. The older Sass syntax uses the .sass file extension and is fairly distinct from CSS, focusing on concise code. The newer Sassy CSS is instead recognised by the .scss extension and is closer in format to CSS standard.

No matter which you choose, a SassScript is what developers write in a Sass or CSS preprocessor before compiling their code into CSS.

Sass vs CSS

Fortunately for CSS preprocessor users, a Sass preprocessor is totally backwards compatible with CSS, and all existing CSS files can easily be converted to Sass.

But where making use of a Sass preprocessor comes into its own is with the range of new features packed just beneath the hood.

These nifty new features that CSS is missing include the use of variables, which are sets of values that are simple to store and reuse. For example, Sass preprocessor variables can be used to set specific hexadecimal colours, avoiding the need to go back and find the right code every time you want to specify the colour of something.

Mixins is another Sass preprocessor feature that helps developers reuse blocks of code throughout a site – essentially creating a template for complex CSS coding. Other features of Sass that help to organise code include loops, nesting, inheritances, and partials. These all help to make your CSS code cleaner and more manageable, as well as reduce redundant code.

Sass for web designers

Taken as a complete package, it’s clear that Sass is very much focused on helping developers create more advanced CSS. And equally importantly, making that CSS simple to manage and maintain.

CSS, and Sass preprocessors in general, offer those quality-of-life improvements all developers and web designers dream of but never get to implement. The golden rule of using Sass should be seen in the context of ‘don’t repeat yourself’.

There’s a reason this is a long-established software engineering principle that is often advocated: make efficient code with minimal repetition and reuse code wherever possible.

So, if you’re struggling to decide on Sass vs CSS, the obvious answer is to choose both.

But you might be wondering if there are any alternatives to Sass? Another popular one is Less, which stands for Leaner Style Sheets, another common CSS preprocessor that offers similar features to Sass while being based on JavaScript. Less can offer a few alternative implementations compared to Sass and can potentially provide you with more control over mixins in some cases.

With all that being said, CSS preprocessors aren’t recommended for CSS beginners. It’s vitally important to understand the basics of the CSS language when starting out. While understanding CSS preprocessors makes advanced CSS coding easier to manage, using them also adds an additional step in the development process, potentially allowing more room for error.

Whether you’re just getting started with CSS, or building complex sites with a preprocessor like Sass, chances are you’ll need a reliable hosting platform to work from.

How to set up Sass

You’ll need to set up Saas into your dev workflow. We’ll use Node.js and NPM (Node Package Manager) in this example, as they’re the most common frameworks to use. 

1. Install it

Luckily on Sass, you can install it globally using these! Open your terminal or command prompt and run:

npm install -g sass

With this command, Sass can be installed globally, meaning you can run it from anywhere on your workstation. 

2. Configure

Now it's time to set up Sass for your project. Begin by creating a new file named “style.scss” – or whatever you want so long as it’s memorable – in your project directory; this will serve as your primary Sass file. You can also create more .scss files to help organise your styles and then import them into style.scss.

To convert your Sass code into CSS, execute the following command in your terminal, making sure to replace style.scss with the correct file path:

sass style.scss style.css

This command will generate a new style.css file from your style.scss, which you can then link to in your HTML. Additionally, you can use the --watch flag to automatically recompile your Sass files whenever you make changes.

sass --watch style.scss:style.css

For an even smoother workflow, consider incorporating Sass into your build process with tools like Grunt or Webpack. These tools not only automate the compilation but can also handle tasks such as minification, vendor prefixing, and source mapping.

Now with your CSS preprocessor configured, you're all set to create more modular, maintainable, and expressive styles for your projects!

When not to use a CSS preprocessor

While CSS preprocessors can greatly improve your web development process, there are instances where they might not be needed. Make sure you weigh the pros and cons to determine the benefits, as well as any potential downsides for your particular project.

  • Small projects: When dealing with smaller projects that have basic CSS needs, the effort required to set up and learn a preprocessor may not be worth it. If your project consists of just a few styles and you don't foresee it becoming more complex, sticking with plain CSS could be a simpler solution.
  • Tight deadlines: Adding a new tool to your workflow can come with a learning curve, which may not be practical if you're facing tight deadlines. If your team isn't already familiar with the preprocessor, the time needed for setup and training could push your project timeline back.
  • Compatibility issues: Although most modern browsers support CSS preprocessors well, there might be times when you need to cater to older or less capable browsers. In these situations, the process of converting preprocessor code to standard CSS could lead to compatibility challenges or necessitate extra workarounds.
  • Basic styling needs: If your project's styling demands are simple and don't require advanced features like complex calculations, mixins, or nested rules, the advantages of using a preprocessor may be limited.

So are CSS preprocessors worth it?

CSS preprocessors, such as Sass, are absolutely worth the time and effort to embed into your workflow. This is because they enhance the efficiency and organisation of CSS writing, simplify your development and allow you to use tons of features from nesting to mixins. What does this mean? More time to focus on your business and explore other features for your site with fewer time constraints!

Plus, CSS preprocessors give you the flexibility needed to tackle complex styling and speed up development with capabilities like colour manipulation and mathematical calculations.

Get in touch today for more details on our full range of solutions, including our Website Builder and hosting, for web designers and developers. Head over to the Fasthosts blog to find even more articles like this one.