A List Apart


Illustration by Kevin Cornell

Why Sass?

A note from the editors: We are pleased to present you with an excerpt from Sass For Web Designers by Dan Cederholm, available now from A Book Apart.

I was a reluctant believer in Sass. I write stylesheets by hand! I don’t need help! And I certainly don’t want to add extra complexity to my workflow. Go away!

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That was the thinking anyway. But the reality is that Sass (and other CSS preprocessors) can be a powerful ally—a tool that any style-crafter can easily insert into their daily work. It took me a while to come around, but I’m sure glad that I did.

And that’s the reason I wanted to write this little book. To share how I’ve been able to use Sass to be more efficient, while maintaining the process I’ve become comfortable with from writing CSS for the last ten years. I had many misconceptions about Sass that prevented me from giving it a go, initially. I was worried I’d have to completely alter the way I write and manage stylesheets. As CSS can be fragile at times, it’s understandable for its authors to be somewhat protective about their creation. Can I get an amen?


So, I’m here to show you how Sass doesn’t have to disrupt your process and workflow, and how it can make your life easier. I’ll demonstrate the various aspects of Sass, how to install it, how to use it, and how it’s helped me in my own projects. With any luck, I just might make you a believer as well.

The Sass elevator pitch

Ever needed to change, say, a color in your stylesheet, and found that you had to find and replace the value multiple times? Don’t you wish CSS allowed you to do this?

$brand-color: #fc3;
a {
color: $brand-color;
nav {
	background-color: $brand-color;

What if you could change that value in one place and the entire stylesheet reflected that change? You can with Sass!

Or how about repeated blocks of styles that are used in various locations throughout the stylesheet?

p {
margin-bottom: 20px; font-size: 14px; line-height: 1.5;
footer {
	margin-bottom: 20px;
	font-size: 14px;
	line-height: 1.5;

Wouldn’t it be fantastic to roll those shared rules into a reusable block? Again, defined only once but included wherever you needed them.

	@mixin default-type {
	margin-bottom: 20px;
	font-size: 14px;
	line-height: 1.5;
p {
@include default-type;
footer {
	@include default-type;

That’s also Sass! And those two extremely simple examples barely scratch the surface as to how Sass makes authoring stylesheets faster, easier, and more flexible. It’s a welcome helper in the world of web design, because anyone that’s created a website knows…

CSS is hard

Let’s face it: learning CSS isn’t easy. Understanding what each property does, how the cascade works, which browser supports what, the selectors, the quirks, and so forth. It’s not easy. Add on top of that the complexity of the interfaces we’re building these days, and the maintenance that goes along with that and—wait, why are we doing this again? It’s a puzzle, and some of us enjoy the eventual completion.

Part of the problem is that CSS wasn’t originally designed to do the things we do with it today. Sure, progress is moving along at a nice clip thanks to rapid browser innovation and implementation of CSS3 and beyond. But we still need to rely on techniques that are, for all intents and purposes, hacks. The float property, for example, was designed to simply align an image within a block of text. That’s it. Yet we’ve had to bend that property to lay out entire interfaces.

Our stylesheets are also immensely repetitive. Colors, fonts, oft-used groupings of properties, etc. The typical CSS file is an extremely linear document—the kind of thing that makes an object-oriented programmer want to tear their hair out. (I’m not an object-oriented programmer, but I have very little hair left. Read into that as you may).

As interfaces and web applications become more robust and complex, we’re bending the original design of CSS to do things it never dreamed of doing. We’re crafty like that. Fortunately, browser makers adopt new CSS features far more rapidly these days, with more efficient and powerful properties and selectors that solve the problems today’s web poses. Features like new layout options in CSS3, border-radius, box-shadow, advanced selectors, transitions, transforms, animation, and so on. It’s an exciting time. And yet, there’s still a lot missing from CSS itself. There are holes to be plugged, and the life of a stylesheet author should be a lot easier.

The DRY principle

If we peer into the world of software engineering (and I much prefer to peer than hang out and get comfortable there), we can quickly see how organization, variables, constants, partials, etc., are an ingrained, crucial way of working for folks building complex systems.

You may have heard of the “don’t repeat yourself” (DRY) principle. Coined and defined by Andy Hunt and Dave Thomas in their book, The Pragmatic Programmer (http://bkaprt.com/sass/1/), DRY declares:

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

The idea is that duplicating code can cause failure and confusion for developers (http://bkaprt.com/sass/2/). It’s common sense as well: write commonly-repeated patterns once, and reuse those bits throughout the application. It’s more efficient and far easier to maintain code this way.

CSS is anything but DRY. At times, it drips with repeated rules, declarations, and values. We’re constantly writing the same snippets of code for colors, fonts, and frequently-used patterns of style throughout our stylesheets. One look through a decent-sized CSS file, and a DRY software developer will weep, first with bewilderment, then frustration.

“How the !@#$ do you maintain this?!” they’ll ask.

“Have I also told you about IE bugs?” you’ll reply with a bit of self-loathing.

So why is CSS so difficult to work with?

We can gather a hint of understanding why CSS has had its syntax limitations over the years from an essay by CSS co-inventor, Bert Bos (http://bkaprt.com/sass/3/):

CSS stops short of even more powerful features that programmers use in their programming languages: macros, variables, symbolic constants, conditionals, expressions over variables, etc. That is because these things give power-users a lot of rope, but less experienced users will unwittingly hang themselves; or, more likely, be so scared that they won’t even touch CSS. It’s a balance. And for CSS the balance is different than for some other things.

The original architects of CSS were concerned with adoption. They (rightfully) wanted as many people as possible creating websites. They wanted CSS to be powerful enough to style web pages and separate content from presentation, while being easy to understand and use. I can certainly respect that. At the same time, we have work to do, and that work is getting more complicated, more nuanced, and more challenging to maintain and to future-proof.

Fortunately, there are options to help us out here, and one of them is Sass.

What is Sass?

Sass is a CSS preprocessor—a layer between the stylesheets you author and the .css files you serve to the browser. Sass (short for Syntactically Awesome Stylesheets) plugs the holes in CSS as a language, allowing you to write DRY code that’ll be faster, more efficient, and easier to maintain.

The Sass website (http://bkaprt.com/sass/4/) describes itself succinctly:

Sass is a meta-language on top of CSS that’s used to describe the style of a document cleanly and structurally, with more power than flat CSS allows. Sass both provides a simpler, more elegant syntax for CSS and implements various features that are useful for creating manageable stylesheets.

So while normal CSS doesn’t yet allow things like variables, mixins (reusable blocks of styles), and other goodies, Sass provides a syntax that does all of that and more—enabling “super functionality” in addition to your normal CSS. It then translates (or compiles) that syntax into regular ol’ CSS files via a command-line program or web-framework plugin.

More specifically, Sass is an extension of CSS3, and its SCSS (“Sassy CSS”) syntax—which we’ll talk about in just a moment—is a superset of CSS3. Meaning, any valid CSS3 document is a valid SCSS document as well. This is integral to Sass being something you can “ease into.” Getting started with Sass syntax is painless, and you can use as little or as much as you’d like. Which also means converting an existing stylesheet from CSS to SCSS can be done in stages, as you learn and pick up more of Sass’s functionality.

Later, when you’ve become fluent with Sass (and it won’t take long), it really does feel like a natural extension of CSS—as if it’s filling holes we all wish were filled by the CSS spec itself. This is why, once I started using Sass, I never once thought it was awkward or laborious—it just feels like CSS should feel. Once you try it, you’ll likely stick with it permanently.

Furthermore, Sass is helping CSS get better. By fast-tracking certain features that aren’t currently possible without the help of a preprocessor, it’s giving CSS authors real-world implementation and feature experimentation. When and if it makes sense, certain Sass functionality could very well inform future CSS specifications.

Sass misconceptions

I mentioned earlier that I was reluctant to try Sass. This was partly due to a lot of misconceptions I had prior to using it. Do I need to know Ruby or advanced command-line shenanigans? Will I need to completely change the way I’ve been writing stylesheets? Will the CSS it outputs be bloated and unreadable?

Thankfully, the answer is “nope” for each of those questions, of course—but I do hear them pop up whenever someone mentions Sass on various internet channels. Let’s clear up a few things.

I’m afraid of the command line!

I am by no means a command-line expert, but I’ve learned a bit here and there over the years—just enough to get me into trouble. I’m not afraid to traverse the file system with it or use Git commands, etc.

That said, I sympathize with designers and front-end developers who don’t want to go there. There’s a command-line phobia that exists among some folks. For Sass, there’s very little command-line action required—in fact, a single command is all you need to grasp. Additionally, there are apps and web frameworks that will obviate the need for the command line. (I’ll be introducing those in the next chapter).

So, if you’re a command-line avoider, don’t let that stop you from trying Sass!

I don’t want to change the way I write CSS!

This was the misconception that I suffered from. I’m particular about the way my stylesheets are set up and organized. There’s a certain amount of craft that goes into the document. But remember, since the SCSS syntax is a superset of CSS3, you don’t have to change anything about the way you write CSS. Commenting, indenting, or not indenting, all your formatting preferences can remain the same when working in .scss files. Once I realized this, I could dive in without fear.

I don’t want Sass to change the way I design!

On the flip side, Sass won’t solve all of your problems or cure your bad habits. Inefficient, bloated stylesheets can be just as inefficient and bloated when using Sass. Good organization and smart thinking still apply here. In fact, there are instances where Sass can magnify bad practices, and we’ll go into that a bit as well. But when used properly and intelligently, Sass can be such a massive assist in creating websites.

Okay. Now that we have the particulars out of the way, let’s start having some fun. I think you’ll be amazed at what Sass can do. In the next chapter, we’ll set up our workflow—how Sass can fit into your process and how easy it is to use the command-line or apps. Let’s get Sassing, people.

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