> For the complete documentation index, see [llms.txt](https://gael-boyenval.gitbook.io/atomic-design-css-architecture-with-itcss-bem-sass/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gael-boyenval.gitbook.io/atomic-design-css-architecture-with-itcss-bem-sass/principles/untitled.md).
# ITCSS
## Inverted triangle architecture (ITCSS)
### What is ITCSS?
Inverted Triangle architecture for CSS.\
A sane, scalable, managed architecture.\
A school-of-thought, not a library.\
A meta framework; a framework for frameworks.\
**Incredibly simple.**
### The ITCSS architecture layers
1. **Settings**: Global variables, config switches.
2. **Tools**: Default mixins and functions.
3. **Generic**: Ground-zero styles (Normalize.css, resets, box-sizing).
4. **Base/Elements**: Unclassed HTML elements (type selectors).
5. **Objects**: Cosmetic-free design patterns.
6. **Components**: Designed components, chunks of UI.
7. **Utilities**: Helpers and overrides.
### The layers are organized following those metrics
* From the generic to the explicit.
* From low specificity to high specificity.
* From global reach to localized reach.
{% hint style="info" %}
**I strongly recommend you to watch** [**the video presentation**](https://www.youtube.com/watch?v=1OKZOV-iLj4) **by Harry Roberts, and read this** [**good article**](https://www.xfive.co/blog/itcss-scalable-maintainable-css-architecture/) **about it. You also can read the** [**PDF version of the slides**](https://csswizardry.net/talks/2014/11/itcss-dafed.pdf) **used in his talk**
{% endhint %}
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter:
```
GET https://gael-boyenval.gitbook.io/atomic-design-css-architecture-with-itcss-bem-sass/principles/untitled.md?ask=
```
The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.