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ResponsiveJS documentation

One page per question — start from what you're trying to do.

Your questionThe page
I have a site — is it right?Getting started — one command, nothing installed, every width judged
I have a site and want to keep it rightAdopting r$ — measure → pin a contract → gate it in CI → only then write constructs
Why this and not clamp() / Percy / axe?Why r$ — the honest comparison, and when not to use it
Something does not behaveTroubleshooting — by symptom
Teach me — I'll build alongThe tutorial — empty page → fluid, measured, contract-pinned landing in 7 steps (~30 min)
How does the model work?Conceptsvalue = f(width), snapshots, the oracle, CSS-first
How do I author responsive behavior in JS/TS?The runtime guider$.: every construct's purpose, gradual examples, customizing & debugging
What's the pattern for MY problem?The pattern catalog — every construct on a real problem, organized by what you're building; three unpacked end to end
How do I validate/score a page?The design guider$(page): measure → model → judge, analyze(), contracts, cutting false positives
How do I test all of this?Testing responsive behavior — what's unit-testable vs what needs a browser, patterns and traps
How do I wire it into CI?CI guide — pipelines, SARIF, baselines strategy
What's the exact signature of X?API reference: runtime · design · contract · cli · core · adapters
How do I use it in React / Vue / Angular?Adapters reference — the lifecycle, per framework
I have no build step (CMS, plain HTML)runtime/global — one <script>, window.r$
A live page using everythingFluid landing example — run it, resize it, read its tutorial
The oracle inside DevToolsThe r$ devtool — sweep, curve inspector, score HUD, contract recorder (load unpacked)

For AI agents (compact, exact I/O — different documents on purpose):

  • Validation reference — commands, exit codes, report JSON shapes, the 27 constraints, contract skeleton, the fix loop
  • Authoring reference — invariants, signatures, construct chooser, the minimal correct pattern
  • r$ for AI agents — the narrative guide: drivers (CDP/eval/agent-browser), contracts as instructions

The aesthetic score is grounded in Ngo, Teo & Byrne (2003), Modelling interface aesthetics, and Birkhoff (1933), Aesthetic Measure — see api/core.md.