Skip to main
Jump Start Sass, by Miriam Suzanne and Kitty Giraudel

Sass Architecture

Excerpt from Jump Start Sass, chapter 11

I’m excited to release Jump Start Sass, a book I co-authored with Kitty Giraudel. Digital copies are available from SitePoint, with print editions sold by O’Reilly. Here’s an excerpt from Chapter 11, Sass Architecture.

See more at SitePoint »

Most CSS and Sass organization systems are based on some concept of user interface “components” or discrete pieces that can be put together to form a complete project. Components can be any size or shape, but they should focus on doing one task independently, and in a reusable way. A button, a drop-down, a calendar, and a search form are all examples of components that can be reused at different places across a project. Thinking about your project as a collection of components will help you towards having an organized and maintainable architecture, whether you’re using Sass or plain CSS.

Because of the way CSS works, the order of your code will also affect its meaning: later code has priority in the cascade over the code before it. Some of the popular branded architectures (the ones you know by name) try to eliminate this feature of the cascade entirely, but I use it as a guide – organizing code from the most general to the most specific – so the priority override makes sense. Code that we want applied generally across the site should come first, growing slowly in specificity and detail as we move towards more unique components and special cases.

I first learned of this approach from Natalie Downe’s wonderful CSS Systems talk in 2008 before I’d ever used Sass. Her architecture at the time started with elements (h2, ol, ul, and so on) grouped by “type”, followed by classes grouped by the “effect” created, and finally IDs grouped by the “component” they affect. These days it’s common practice to avoid IDs altogether, and break elements into smaller pieces, but the concept remains the same: global defaults first, followed by site-wide patterns and broad layouts, and finally, more specific modules, themes, and overrides.

Sass projects include another category of site-wide defaults not found in CSS: code with no output at all – such as variables, functions, and mixin definitions. Many people (myself included) break that code into its own set of partials, to be imported anywhere it might be useful. I have a complete folder just for site-wide Sass helpers and configuration that don’t result in output. Those files act as a single, definitive, and reusable configuration that defines the boundaries of a project. By ensuring your configuration is output-free, you can import it anywhere without worrying about duplicated or unwanted styles.

Here are some guidelines for thinking about architecture:

  1. Break your code into the smallest logical component partials.
  2. Organize your partials into grouped folders based on specificity.
  3. Import those partials into one master file in order of specificity.

However, many variations do exist on the specific ways people implement those ideas.

You may also find that a lot of the branded systems developed by and for massive companies with large-scale needs don’t always translate to smaller teams and products. Every project has different requirements, so you should never assume that the best solution for InstaFace or MyPinBook is going to be the best solution for you.

  1. Sass logo in black
on top of bright oklch color gradient
    Link post type

    Sass Color Spaces (Request for Comments)

    A new proposal for color management in Sass

    There’s been a lot of exciting work in the CSS color specifications lately, and since the new features are already starting to land in browsers, we’ve been preparing to add support in Sass as well. My proposal for that is published and ready for public feedback!

    see all Link posts
  2. fragment of an inverted triangle with the cascade --
cascade layers are highlighted below element-attached styles
and above specificity
    Link post type

    A Complete Guide to CSS Cascade Layers

    Cascade layers are a new CSS feature that allows us to define explicit contained layers of specificity, so that we have full control over which styles take priority in a project without relying on specificity hacks or !important. This guide is intended to help you fully understand what cascade…

    see all Link posts
  3. A whole CSS-art cabinet of single-div objects drawn by Lynn Fisher,
from a mirror and skull, to abacus, clock, viewfinder, plants,
snow globe, hot air balloon, and lightsaber.
    Link post type

    Very Extremely Practical CSS Art

    CSS-Tricks asked a number of web builders the same question…

    What is one thing you learned about building websites this year?” I’ve always enjoyed the CSS art people create, but I’ve never ventured into it much myself. I’m familiar with many of the tricks involved, but still find it surprising every time: the way people are able to…

    see all Link posts