AI Tools for Modern CSS
Get AI coding agents to write modern, native CSS instead of floats, JavaScript hacks, and preprocessor workarounds. Free, client-side, no sign-up.
Generators
CSS Rules Generator
Pick the CSS categories you care about and export an AGENTS.md or CLAUDE.md rules file that tells AI agents to use modern CSS instead of legacy hacks.
Generate rules → Modern CSS Prompt Library
Copy-ready prompts that push Claude, Cursor, Copilot, and other agents toward native CSS: container queries, :has(), scroll-driven animation, and more.
Browse prompts → Ready-made files
AGENTS.md
The full modern CSS pattern reference, organized by category. Drop it into any agent that reads AGENTS.md.
modern-css.com/AGENTS.md llms.txt
A machine-readable index of the site for language models, following the llms.txt convention.
modern-css.com/llms.txt Cheatsheet
Old CSS hacks mapped to their modern native replacements, in one lookup table.
modern-css.com/cheatsheet