GuideTools
Josh W. Comeau's blog
Interactive, deeply explained articles on CSS, layout, animation and polish.

What it is
Josh Comeau writes some of the best educational content on the web about CSS and front-end craft: the interactive guides to Flexbox and Grid, a modern CSS reset, designing beautiful shadows, spring animations, and many details of building things that feel good. Free articles; paid courses.
Why it’s here
The articles on shadows, the CSS reset and "designing beautiful focus states" are worth handing to an agent verbatim. The interactive guides are the best way to learn layout yourself.
Best for
- learning CSS properly
- shadow and depth
- focus states
- a good CSS reset
Can my agent use this?
Agent good agent friendlinessYes. The articles are public and detailed. Link a specific article (for example the CSS reset or the shadows guide) and ask your agent to apply it.
Good: Publicly accessible and useful to reference, but the agent will need to interpret it rather than install it.
Access methods
- Public website
- Copy/paste
Related resources
Refactoring UI 
Refactoring UI
The book that teaches developers to design, by the creators of Tailwind.
Guidelimited agent friendlinessStaff pickUsed by meLaws of UX 
Laws of UX
The psychology principles behind good interfaces, one page each.
GuideFreegood agent friendlinessAccessible Palette 
Accessible Palette
Build colour scales where every step has predictable, accessible contrast.
ToolFreegood agent friendlinessChrome DevTools MCP 
Chrome DevTools MCP
Let your agent inspect, debug and profile a live Chrome tab.
MCP serverFreeOpen sourceexcellent agent friendliness